2021/05/15 更新

写真a

ヤマガタ タカユキ
山縣 貴幸
YAMAGATA Takayuki
所属
教育研究院 自然科学系 生産デザイン工学系列 助教
工学部 工学科 助教
職名
助教
外部リンク

学位

  • 博士(工学) ( 2009年3月   東北大学 )

研究キーワード

  • 可視化

  • 混合

  • 安全工学

  • 数値流体力学

  • 空力騒音

  • PIV

  • 配管減肉

  • 物質輸送

研究分野

  • ナノテク・材料 / エネルギー化学

  • ものづくり技術(機械・電気電子・化学工学) / 流体工学

  • 情報通信 / ロボティクス、知能機械システム

  • 情報通信 / 機械力学、メカトロニクス

  • 社会基盤(土木・建築・防災) / 安全工学

  • 社会基盤(土木・建築・防災) / 社会システム工学

  • 情報通信 / 機械力学、メカトロニクス

▶ 全件表示

経歴(researchmap)

  • 新潟大学   工学部 機械システム工学科 生産システム   助教

    2013年10月 - 現在

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  • 新潟大学   工学部   助教

    2009年4月 - 2013年9月

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  • 新潟大学   自然科学研究科 材料生産システム専攻   助教

    2009年4月 - 2013年9月

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経歴

  • 新潟大学   工学部 工学科   助教

    2017年4月 - 現在

  • 新潟大学   生産システム   助教

    2013年10月 - 2017年3月

  • 新潟大学   自然科学研究科 材料生産システム専攻   助教

    2009年4月 - 2013年9月

  • 新潟大学   工学部   助教

    2009年4月 - 2013年9月

学歴

  • 東北大学   大学院工学研究科   バイオロボティクス専攻

    - 2009年3月

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  • 東北大学   工学部   機械電子工学科

    - 2004年3月

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所属学協会

委員歴

  • 可視化情報学会   代議員  

    2013年6月 - 2015年5月   

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    団体区分:学協会

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  • 日本機械学会北陸信越支部   商議員  

    2013年3月 - 2015年2月   

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    団体区分:学協会

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論文

  • Effect of Rotation and Revolution on Performance of Blade-Free Planetary Mixer 査読

    Takayuki Yamagata, Nobuyuki Fujisawa

    Journal of Flow Control, Measurement & Visualization7 ( 1 ) 1 - 10   2019年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.4236/jfcmv.2019.71001

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  • Influence of elbow curvature on flow and turbulence structure through a 90° elbow 査読

    Yuya Ikarashi, Taku Uno, Takayuki Yamagata, Nobuyuki Fujisawa

    Nuclear Engineering and Design339   181 - 193   2018年12月

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    © 2018 Elsevier B.V. The influence of elbow curvature on the flow field of a 90° elbow was studied experimentally to understand the flow and turbulence structure in the elbow using planar and stereo particle image velocimetry (PIV) measurements. Three elbows with different radius to diameter ratios (1.0, 1.2, and 1.5) were investigated in the Reynolds number range of Re = (3–10) × 104. The experimental results showed that the mean velocity decreased and turbulence intensities increased along the inner wall in the second half of the elbow, and similar observations were made in all of the elbows. However, variations in these quantities increased with decreasing radius ratio. This was caused mainly by the occurrence of flow separation on the inner wall, near the elbow outlet, for smaller radius ratios. Similarly, flow separation on the inner wall was promoted at lower Reynolds numbers. Cross-sectional velocity field measurements at the elbow outlet using stereo PIV showed the presence of a pair of counter-rotating vortices, which increased in mean velocity and turbulence energy on the inner wall with decreasing radius ratios of the elbow. This result was well reproduced in the contour of the first proper orthogonal decomposition (POD) mode. In the POD analysis, opposite signs of the high POD mode were formed on both sides of the inner wall and the peak of the POD mode increased with decreasing radius ratio.

    DOI: 10.1016/j.nucengdes.2018.09.011

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  • Damping effect on impact pressure from liquid droplet impingement on wet wall 査読

    K. Fujisawa, T. Yamagata, N. Fujisawa

    Annals of Nuclear Energy121   260 - 268   2018年11月

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    © 2018 Elsevier Ltd Damping of the impact pressure from liquid droplet impingement (LDI) on a wet wall was studied by numerical simulation and experiment. The numerical simulation was carried out for the impact of an axisymmetric spherical droplet on a wet wall using a compressible form of the Euler equations combined with the stiffened gas equation. The impact pressures on the wall were highly damped by the influence of the liquid film prevailing over the wet wall, and the damping effect was formulated as a function of the liquid-film thickness to droplet diameter. The physical mechanism of the liquid-film damping effect is due to the two-stage compression during LDI and its weakening by the diffraction of the shock wave propagated in the liquid film. In order to understand the liquid-film damping effect obtained from the numerical simulation, experiments on LDI erosion on a wet wall were carried out for various liquid temperatures, which generated a thinner liquid film on the wall at higher temperatures by the viscous effect. The experimental results indicated that the LDI erosion rate increased with rising liquid temperatures, which corresponds to the erosion-rate growth at thinner liquid-film thicknesses. This result is consistent with the liquid-film damping effect obtained from the numerical simulation.

    DOI: 10.1016/j.anucene.2018.07.008

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  • Experimental and numerical studies on Aeolian tone from D-shaped cylinder 査読

    T. Yamagata, N. Saito, N. Fujisawa

    Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science   2018年11月

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    © 2017, IMechE 2017. Aeolian tone generated from a D-shaped cylinder in a stream was studied experimentally and numerically for various width-to-height ratios of the cross-sectional shape. The sound pressure level and unsteady fluid forces were measured experimentally for a circular cylinder and D-shaped cylinders with width-to-height ratios of 0.5, 1, and 1.5. The experimental results revealed that the Aeolian tone and lift fluctuation of the D-shaped cylinders were smaller than those of the circular cylinder. Flow structures around the circular and D-shaped cylinders were investigated by using large eddy simulation to understand the mechanism of the reduction of Aeolian tone from the D-shaped cylinders. The numerical results indicated that the D-shaped cylinder with a width-to-height ratio of 0.5 showed similar velocity fluctuations with the circular cylinder, but the shortening of the streamwise length resulted in a reduction of the sound pressure level. Moreover, the velocity fluctuations in the wake decreased in the D-shaped cylinders with width-to-height ratios of 1 and 1.5, resulting from suppression of the vortex shedding near the cylinder.

    DOI: 10.1177/0954406217747912

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  • Simultaneous observation of cavitation collapse and shock wave formation in cavitating jet 査読

    Nobuyuki Fujisawa, Yasuaki Fujita, Keita Yanagisawa, Kei Fujisawa, Takayuki Yamagata

    Experimental Thermal and Fluid Science94   159 - 167   2018年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Elsevier Inc.  

    In this study, the mechanism of cavitation erosion in the cavitating jet discharging from a cavitator nozzle into a still water environment was examined through simultaneous observations of cloud collapse behavior and shock wave formation with and without wall. The simultaneous observations of the cloud collapse and shock wave formation were conducted by time-resolved shadowgraph and laser schlieren methods, respectively, while the impulsive signal on the wall was synchronously detected by an acceleration sensor. The time-resolved shadowgraph and laser schlieren images indicated that some shock waves were occurred at the instant of cloud collapse during the periodic behavior of the cavitating jet, which results in the impulsive forces on the wall. To a large extent, the shock waves originated from the near-wall region, and they induced the impulsive forces on the wall
    in the case without wall, shock wave formation was observed in a similar distance from the nozzle with a broad distribution from the origin along the jet centerline. These results indicate that the cavitating-jet erosion occurs due to the cloud collapse near the wall, where some shock waves are generated and results in the erosion of the wall.

    DOI: 10.1016/j.expthermflusci.2018.02.012

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  • Liquid droplet impingement erosion on groove roughness 査読

    Kei Fujisawa, Takayuki Yamagata, Nobuyuki Fujisawa

    Nuclear Engineering and Design330   368 - 376   2018年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Elsevier Ltd  

    A study of erosion mechanism during the liquid droplet impingement (LDI) on a rough surface was conducted using both numerical simulation and experiments. The numerical simulation was carried out for the LDI on single groove roughness utilizing the two-phase full Eulerian approach based on the high-resolution finite volume method to understand the evolution of the droplet deformation and the wall pressure distribution. The numerical results for the LDI on a large groove roughness showed that the first and the second impacts occurred close to the first contact location of the droplet on the wall, which was similar to the LDI on a smooth surface. The largest impact occurred by the third impact at the groove bottom, which was caused by the side-jet focusing and droplet focusing generated from the contact edge of the droplet. It was also found that the maximum wall pressure at the groove bottom increased with the increase in the groove roughness parameter that represented the geometrical ratio of the groove depth to the droplet diameter. In addition to the numerical studies, the erosion behavior of LDI on single groove roughness was observed experimentally using a Scanning Electron Microscope (SEM) after spray jet impingement on an aluminum specimen with various groove roughness parameter. The experimental results showed that the LDI erosion on the large groove roughness started from the groove bottom, while the LDI erosion on the small groove roughness started from the groove edge and the groove bottom. These experimental findings are well correlated with the maximum wall pressure distributions obtained from the numerical results.

    DOI: 10.1016/j.nucengdes.2018.02.021

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  • Observation of large-scale structure in flickering diffusion flame by time-resolved particle image velocimetry and shadowgraph imaging 査読

    Nobuyuki Fujisawa, Kazuki Sakai, Takayuki Yamagata

    Experimental Thermal and Fluid Science92   286 - 294   2018年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Elsevier Inc.  

    In order to understand the flow structure of a flickering flame, time-resolved observations are carried out of the velocity and density fields in a diffusion flame in co-flow using particle image velocimetry (PIV) and shadowgraph imaging, respectively. The PIV measurement combined with invalid velocity vector analysis using proper orthogonal decomposition (POD) allows for the high spatial resolution measurement of the velocity field in the flame, while the shadowgraph images show the high-temperature contour and soot formation of the flame. These experimental results indicate a periodic variation in the flow field and soot structure of the flickering flame. The observation of the velocity field shows that the periodic inflow and outflow are generated in the outer layer of the flame near the burner, which promotes the flow acceleration in the vertical direction leading to clip-off behavior. It is found that the vorticity contour evaluated from the velocity field matches well with the high-temperature contour observed in the shadowgraph images. Further examination of the flow structure is carried out using the first two POD modes, which demonstrate the presence of counter-rotating vortices in the outer flame contributing to stretching of the flame due to the clip-off motion in the flame.

    DOI: 10.1016/j.expthermflusci.2017.11.026

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  • Experiments on liquid droplet impingement erosion on a rough surface 査読

    N. Fujisawa, S. Takano, K. Fujisawa, T. Yamagata

    Wear398-399   158 - 164   2018年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Elsevier Ltd  

    Liquid droplet impingement (LDI) erosion on a rough surface was studied experimentally in the initial stage of erosion using spray-jet impingement on various levels of sandpaper roughness and single groove roughness. The experimental results using an aluminum specimen indicated that the incubation period decreased and the erosion rate increased with increasing the relative roughness, defined as the ratio of roughness height to droplet diameter, in a range of small relative roughness. The growth of the erosion rate in a large relative roughness is almost constant for the sandpaper roughness with increasing the relative roughness, while the erosion rate for the groove roughness decreased at large relative roughness. Therefore, the erosion rate of the groove roughness indicated a peak at small relative roughness. This might be due to the influence of smooth surface surrounding the single groove roughness. A scanning electron microscope (SEM) observation for the small relative roughness of groove showed that erosion was started on the sidewall of the grooves and was followed by the penetration of erosion perpendicular to the groove. The erosion initiation points shifted from the sidewall to the bottom of the groove with increasing the relative roughness, which might be due to the effective impact angle variation across the groove.

    DOI: 10.1016/j.wear.2017.12.003

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  • Mass and momentum transfer characteristics in 90° elbow under high Reynolds number 査読

    Shoichi Taguchi, Yuya Ikarashi, Takayuki Yamagata, Nobuyuki Fujisawa, Fumio Inada

    International Communications in Heat and Mass Transfer90   103 - 110   2018年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Elsevier Ltd  

    Mass and momentum transfer characteristics in a 90° elbow with a radius to pipe diameter ratio of 1.5 are studied experimentally with the aid of the plaster dissolution method, planar velocity measurement by particle image velocimetry (PIV), and surface flow visualization in the Reynolds number (Re) range of 5 × 104 to 20 × 104. The experimental results indicate that the most significant change in mass transfer distribution occurs on the inner wall of the elbow. The mass transfer coefficient increases along the centerline of the first half of the elbow and decreases in the second half with increasing Reynolds number. The near-wall velocity measurements by PIV show that the flow accelerates on the first half of the inner wall and decelerates on the second half, which contributes to the growth of the turbulent intensities on the second half of the inner wall. The surface flow visualization indicates that the secondary flow is weak on the inner wall of the elbow with higher Reynolds number. These results show that the mass transfer characteristics change on the inner wall of the elbow with increase in the Reynolds number, even when it is larger than Re = 5 × 104.

    DOI: 10.1016/j.icheatmasstransfer.2017.11.006

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  • Time-resolved observations of pit formation and cloud behavior in cavitating jet 査読

    N. Fujisawa, T. Kikuchi, K. Fujisawa, T. Yamagata

    WEAR386-387   99 - 105   2017年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE SA  

    Time-resolved observations of pit formation and cloud structure in a cavitating jet are carried out to understand the erosion mechanism of a cavitating jet issuing from a converging and diverging nozzle in a still water environment. Pit formation is detected by a sensor made of gold film (0.2 mu m in thickness) glued to a transparent glass plate, and the number and size of the pits are evaluated from digital image analysis. High-speed camera shadowgraph imaging allows observation of the cloud structure in the cavitating jet, which captures the cavitation cloud collapse combined with the time-difference analysis. The radial distribution of pits is in close agreement with the erosion depth distribution evaluated from the weight-loss profiles of an aluminum specimen in a cavitating jet. The pit distribution in the cloud collapse is well reproduced in the time-difference analysis. Furthermore, simultaneous observations of the pit and cloud structures show that pits are formed on the wall at the instant of cloud collapses during the periodic behavior of the cavitating jet.

    DOI: 10.1016/j.wear.2017.06.006

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  • Mass and momentum transfer characteristics in and downstream of 90 degrees elbow 査読

    Yuya Ikarashi, Shoichi Taguchi, Takayuki Yamagata, Nobuyuki Fujisawa

    INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER107   1085 - 1093   2017年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Mass and momentum transfer characteristics in and downstream of a 90 elbow are studied experimentally with the aid of the plaster dissolution method, surface flow visualization in the elbow and the cross-sectional velocity field measurement by stereo particle image velocimetry (SPIV) downstream of the elbow. The experiments are carried out for the elbow with the radius to diameter ratio 1.5 at moderate Reynolds number Re = 5 x 10(4). The mass transfer measurements in the elbow indicate that the major change of mass transfer coefficient is observed along the inner wall of the elbow, where low mass transfer coefficient is found in the first half of the inner wall and it increases abruptly in the second half of the elbow, which is followed by a gradual recovery of the mass transfer in the downstream, while the mass transfer on other wall does not change so much with that of the straight pipe. These features are mainly due to the flow acceleration in the first half of the inner wall and the following flow separation in the second half of the inner wall, where the high turbulent energy production is expected from the SPIV measurement downstream of elbow. These results indicate that the mass transfer coefficient in and downstream of the elbow is highly modified by the flow separation and secondary flow in the elbow, which may generate the high turbulent energy production in the second half of the inner wall in the elbow. (C) 2016 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.ijheatmasstransfer.2016.11.014

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  • Characterization of exchange flow in vertical pipes of circular and square cross-sections under unstable density gradient 査読

    A. Maeda, N. Fujisawa, T. Yamagata, H. Muramatsu

    INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER82   81 - 88   2017年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The exchange flows in a buoyancy driven forced flow in vertical pipes of circular and square cross-sections were studied experimentally and the flow structure was examined by proper orthogonal decomposition (POD) analysis. The experiments were carried out in the vertical pipes issuing into a still brine water environment and the flow fields were visualized by the laser-induced fluorescence (LIF) technique. The flow visualization study showed that the critical inflow condition was deviated from the purging boundary due to the influence of hysteresis, and they are shifted to the high Froude numbers in the square pipe compared to the circular one. The POD analysis of the exchange flow indicates that the fluctuating energy is increased in the lower POD modes due to the formation of large-scale structure of the exchange flow. It is found from the analysis that the exchange flow in the low Reynolds number is promoted at the corners of the cross section in the square pipe, while it is randomly distributed in the circular pipe. This corresponds to an increased critical Froude number in the square pipe than that of the circular pipe, which is due to the presence of exchange flow through the corners. With increasing the Reynolds numbers, the flow becomes turbulent and the scale of the exchange flow is decreased and restricted to the near-wall region, while the location of the exchange flow becomes random along the pipe wall irrespective of the cross-sectional shape of the pipes. (C) 2017 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.icheatmasstransfer.2017.02.011

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  • Numerical study on non-axisymmetric wall thinning in pipelines with swirling flow 査読

    Takayuki Yamagata, Ai Ishizuka, Nobuyuki Fujisawa

    ANNALS OF NUCLEAR ENERGY101   196 - 202   2017年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    In order to understand the mechanisms of non-axisymmetric pipe-wall thinning in the Mihama nuclear power plant accident of 2004, a numerical simulation of pipe-wall thinning in an elbow-orifice pipeline with swirling flow was carried out based on mass and momentum transfer equations with a standard k-epsilon model of turbulence at a Reynolds number of 5.8 x 10(6). The pipe-wall thinning was evaluated on the basis of the mass transfer coefficient using the diffusion coefficient of ferrous iron in bulk water flow. The numerical simulation revealed that swirling flow with a certain level of swirl intensity generates a spiral motion downstream of the elbow and sustains a longer distance than expected from an elbow flow without swirl. This type of non-axisymmetrical flow triggers strongly biased flow at the orifice, which results in non-axisymmetric pipe-wall thinning downstream of the orifice. (C) 2016 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.anucene.2016.09.040

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  • Mass transfer measurements on periodic roughness in a circular pipe and downstream of orifice 査読

    Nobuyuki Fujisawa, Kazuya Uchiyama, Takayuki Yamagata

    INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER105   316 - 325   2017年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    This paper describes the mass transfer characteristics on periodic roughness in a circular pipe and that downstream of an orifice. The mass transfer enhancement ratio of the rough pipe with respect to the smooth pipe are measured by the plaster dissolution method for various combinations of roughness height and wavelength of the periodic roughness, and the influence of roughness on the mass transfer enhancement is examined experimentally. The mass transfer enhancement on periodic roughness is highly increased with increasing the roughness parameter, defined by the roughness height to the wavelength. It is found that the mass transfer enhancement of rough pipe is more than 2 times larger than that of the smooth pipe, which is due to 3the formation of the local recirculating region over the periodic roughness. On the other hand, minor mass transfer enhancement is observed on the flow downstream of an orifice. The examination of the flow and mass transfer over the periodic roughness and that downstream of orifice is carried out by the numerical simulation with low-Reynolds number k-epsilon model. The result indicates that the formation of local recirculating region on the periodic roughness is the major source of mass transfer enhancement on the rough pipe, while the minor mass transfer enhancement downstream of the orifice is attributed to the effect of separating shear layer originating from the orifice edge on the wall, which is dominant over the local effect of recirculating flow on the periodic roughness downstream of the orifice. (C) 2016 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.ijheatmasstransfer.2016.10.002

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  • Influence of Co-flow on Flickering Diffusion Flame 査読

    N. Fujisawa, Y. Matsumoto, T. Yamagata

    FLOW TURBULENCE AND COMBUSTION97 ( 3 ) 931 - 950   2016年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER  

    The influence of air co-flow on flickering methane diffusion flame was studied experimentally using the image processing technique and the proper orthogonal decomposition (POD) analysis. The flickering of the flame is characterized by the mean height, the oscillation amplitude and the Strouhal number, which are measured by the digital image analysis of the diffusion flame. The experiments are carried out for various combinations of burner diameters, fuel velocities and co-flow velocities. With increasing the velocity ratio of the co-flow to the fuel flow, the oscillation amplitude is decreased and the Strouhal number is increased slightly in proportional to the inverse Froude number, while the frequency jump occurs in the low co-flow velocity ratio. These results are commonly observed in all the burners of different diameters, while the critical co-flow velocity ratio to suppress the flickering is found to be increased with increasing the burner diameters due to the influence of Froude number. The POD analysis of the flickering flame shows that the flickering energy is dominant in the first two POD modes and they are axisymmetric except for the zero co-flow velocity case and fully suppressed case. The correlation of POD coefficients in the first two fluctuating POD modes suggests the suppression of large-scale structure of flickering due to the influence of co-flow.

    DOI: 10.1007/s10494-016-9730-9

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  • Grid convergence property of three-dimensional measurement-integrated simulation for unsteady flow behind a square cylinder with Karman vortex street 査読

    Takayuki Yamagata, Toshiyuki Hayase

    Journal of Flow Control, Measurement & Visualization4 ( 4 ) 125 - 142   2016年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

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  • Simultaneous shadowgraph imaging and acceleration pulse measurement of cavitating jet 査読

    R. Watanabe, K. Yanagisawa, T. Yamagata, N. Fujisawa

    WEAR358-359   72 - 79   2016年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE SA  

    The variations of cloud structure and erosion characteristics of a cavitating jet are experimentally studied by optical and SEM microscope observations, measurement of erosion characteristics and simultaneous shadowgraph imaging combined with the acceleration pulse measurement. The time difference image analysis of the shadowgraphs allows the detection of the near-wall collapsed bubbles in the periodic development of the cavitating jet, while the simultaneous acceleration pulse measurement indicates the generation of acceleration pulses at the same instant of bubble collapse near specimen surface. These results indicate that the generation of acceleration pulses are highly correlated with the collapsed bubbles behind the cloud in the shrinking motion, which triggers the cavitation bubble collapse and leads to the erosion damage on the specimen. It is found from the image analysis that the erosion distributions on the test specimen are well reproduced in the time-difference images of the shadowgraphs, which indicates the sudden intensity growth near the wall due to the cavitation collapse. This result suggests that the collapse of the cavitation bubbles near the specimen surface is correlated with the erosion distribution on the specimen surface in the cavitating jet. (C) 2016 Published by Elsevier B.V.

    DOI: 10.1016/j.wear.2016.03.036

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  • Numerical analysis on the wall-thinning rate of a bent pipe by liquid droplet impingement erosion 査読

    Nobuyuki Fujisawa, Keitaro Wada, Takayuki Yamagata

    ENGINEERING FAILURE ANALYSIS62   306 - 315   2016年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    This paper presents a numerical analysis of liquid droplet impingement (LDI) erosion in the pipeline of nuclear/fossil power plants. The numerical method is based on combining a Eulerian/Lagrangian computational fluid dynamics (CFD) model with an erosion model to consider various aspects of LDI erosion, such as the influence of the droplet velocity, diameter, number density, impingement angle, material hardness, liquid-film thickness, and erosion depth on the wall-thinning rate. A numerical analysis of the erosion depth distribution was carried out for the LDI erosion of a bent pipe downstream of an orifice at the Onagawa power plant incident in 2007. The results were compared with existing erosion models, and the variations in the peak erosion depths were examined. The present model results showed reasonable agreement with the prototype results at the location and the erosion depth distribution of the bent pipe. The comparison showed the importance of the liquid film and erosion depth to predicting the LDI erosion characteristics. (C) 2016 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.engfailanal.2016.01.005

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  • Attenuation of wall-thinning rate in deep erosion by liquid droplet impingement 査読

    Nobuyuki Fujisawa, Takayuki Yamagata, Keitaro Wada

    ANNALS OF NUCLEAR ENERGY88   151 - 157   2016年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    This paper describes an experimental study on the wall-thinning rate in deep erosion by liquid droplet impingement (LDI) in a pipeline for application to nuclear/fossil power plant. The experiment is carried out in a spray jet apparatus, which allows the evaluation of local wall-thinning rate by the LDI erosion. The surface contour of erosion and the wall-thinning rate are measured and the observation by scanning electron microscope (SEM) is carried out in this experiment. The experimental result indicates that the wall-thinning rate is highly attenuated and the macro structure on the erosion surface grows with an increase in the erosion depth, which is due to the influence of the liquid film over the erosion surface. The erosion model for predicting the wall-thinning rate in deep erosion is proposed by introducing the attenuation factor with a function of erosion depth. The introduction of attenuation factor with liquid-film effect shows a better correlation with the experimental data, and the accuracy of correlation is improved by a factor of 2. (c) 2015 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.anucene.2015.10.024

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  • Aeolian Tone from a Semi-Circular Cylinder in a Stream 査読

    Takayuki Yamagata, Nozomi Saito, Nobuyuki Fujisawa

    Journal of Flow Control, Measurement & Visualization4 ( 1 ) 30 - 37   2016年1月

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  • Influence of swirling flow on mass and momentum transfer downstream of a pipe with elbow and orifice 査読

    Tsuyoshi Takano, Yuya Ikarashi, Kazuya Uchiyama, Takayuki Yamagata, Nobuyuki Fujisawa

    INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER92   394 - 402   2016年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The influence of swirling flow on mass and momentum transfer downstream of a pipe with elbow and orifice is studied experimentally. The experiments are carried out in the pipe at Reynolds number Re = 3 x 10(4) for various magnitudes of swirl intensity up to 0.9 driven by the rotary swirler. The mass transfer coefficient and the cross-sectional velocity field downstream of the orifice are measured by the plaster dissolution method and the stereo PIV, respectively. It is found that the mass transfer coefficient and the turbulent energy increases gradually with increasing the swirl intensity, while they become non-axisymmetric downstream of the orifice for the swirl intensity larger than 0.6 at the inlet of the elbow, which is followed by the saturation at higher swirl intensity. The maximum mass transfer coefficient is found to have a peak at one diameter downstream of the orifice and it reaches 6 times larger value than that of the straight pipe without swirling flow. The behavior of the maximum mass transfer coefficient with respect to the swirl intensity is similarly observed in the near-wall turbulent energy. (C) 2015 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.ijheatmasstransfer.2015.08.087

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  • Onset of exchange flow in combined buoyancy and forced pipe flow in unstable density gradient 査読

    A. Maeda, T. Yamagata, N. Fujisawa

    INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER70   9 - 14   2016年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The onset of exchange flow and the flow structure in a combined buoyancy and forced pipe flow are experimentally studied at Reynolds number up to 7000. The experiment is carded out in a vertical pipe flow of water issuing into a still brine water environment of various concentrations and flow rates. The critical Froude number for the onset of exchange flow is evaluated by the laser-induced fluorescence technique and the velocity fields near the pipe exit are measured by the particle-image velocimetry. The critical Froude number in the laminar regime increases with increasing the Reynolds number and the onset of inflow and the purging of the exchange flow are deviated due to the hysteresis effect, while it is not observed in the turbulent regime. It is found that the laminar exchange flow is characterized by the large-scale structure and the turbulent exchange flow is featured by the small-scale structure near the wall. The enhancement of velocity fluctuation near the pipe exit is clearly observed in the laminar regime due to the occurrence of exchange flow, while it is limited to the near-wall region in the turbulent regime. (C) 2015 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.icheatmasstransfer.2015.11.003

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  • Characterization of pipe-flow turbulence and mass transfer in a curved swirling flow behind an orifice 査読

    N. Fujisawa, R. Watanabe, T. Yamagata, N. Kanatani

    ERCOFTAC Series23   225 - 235   2016年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:Springer Netherland  

    This paper deals with the extraction of turbulent structure correlated with the wall mass transfer in a curved swirling pipe flow behind an orifice. The crosssectional velocity field behind the orifice is measured by the Stereo Particle Image Velocimetry (SPIV) and the results are analyzed by the proper orthogonal decomposition (POD). The instantaneous velocity field shows the asymmetric vortex structure in the cross section due to the combined effect of the swirling flow and the secondary flow generated at the upstream elbow. The POD analysis indicates that the highly turbulent flow is generated on the upper left-hand side of the pipe in the lower POD modes suggesting the occurrence of high wall-thinning rate due to the mass transfer enhancement, while that of the higher modes do not show such asymmetry. This result suggests that the lower POD modes of the velocity field contribute to the non-axisymmetric pipe-wall thinning behind an orifice in a curved swirling flow.

    DOI: 10.1007/978-3-319-20388-1_20

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  • Shadowgraph Imaging of Cavitating Jet 査読

    Ryuta Watanabe, Takayuki Kikuchi, Takayuki Yamagata, Nobuyuki Fujisawa

    Journal of Flow Control, Measurement & Visualization3 ( 3 ) 106 - 110   2015年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

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  • The influence of material hardness on liquid droplet impingement erosion 査読

    Nobuyuki Fujisawa, Takayuki Yamagata, Shotaro Takano, Kengo Saito, Ryo Morita, Kazutoshi Fujiwara, Fumio Inada

    NUCLEAR ENGINEERING AND DESIGN288   27 - 34   2015年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE SA  

    This paper describes the experimental study on the liquid droplet impingement erosion of metal materials to understand the influence of material hardness on the erosion rate. The experiment is carried out using a water spray jet apparatus with a condition of relatively thin liquid film thickness. The metal materials tested are pure aluminum, aluminum alloy, brass, mild steel, carbon steel and stainless steel. The liquid droplets considered are 30 +/- 5 mu m in volume average diameter of water, which is the same order of droplet diameter in the actual pipeline in nuclear/fossil power plants. In order to understand the influence of material hardness on the liquid droplet impingement erosion, the scanning electron microscope (SEM) observation on the eroded surface and the measurement of erosion rate are carried out in the terminal stage of erosion. The experimental results indicate that the erosion rates are expressed by the droplet velocity, volume flux, Vickers hardness and the liquid film thickness, which are fundamentals of the liquid droplet impingement erosion. The empirical formula shows that the power index for droplet velocity dependency is found to be 7 with a scattering from 5 to 9 depending on the materials, while the power index for Vickers hardness dependency is found as -4.5. (C) 2015 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.nucengdes.2015.03.016

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  • Non-axisymmetric wall-thinning downstream of elbow-orifice pipeline in swirling flow 査読

    Nobuyuki Fujisawa, Takayuki Yamagata, Nobuaki Kanatani, Ryuta Watanabe

    ANNALS OF NUCLEAR ENERGY80   356 - 364   2015年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The non-axisymmetric wall-thinning leading to a pipeline break is studied in a scaled model experiment in a water tunnel. The pipeline consists of an elbow, an orifice and a straight pipe between them. The measurement of velocity field is carried out downstream of the orifice using stereo Ply and the spatial correlation of velocity fluctuations is analyzed by snapshot Proper Orthogonal Decomposition (POD), while the mass transfer coefficient is measured by a benzoic acid dissolution method. These measurements are carried out at Reynolds number Re = 3 x 10(4) with and without swirl. It is found that the non-axisymmetric flow and mass transfer is found downstream of the orifice due to the combined influence of the secondary flow in the elbow and the swirling flow. The POD analysis indicates that non-axisymmetric velocity field is generated in the first two POD modes, which suggests the structural change in the velocity field downstream of the orifice, such as the non-axisymmetric growth of the velocity and turbulent energy in the lower POD modes. It is also found that the near-wall turbulent energy distribution is correlated with the measurement of mass transfer coefficient. (C) 2015 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.anucene.2015.01.043

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  • Mechanism of non-axisymmetric pipe-wall thinning in pipeline with elbow and orifice under influence of swirling flow 査読

    Nobuyuki Fujisawa, Nobuaki Kanatani, Takayuki Yamagata, Tsuyoshi Takano

    NUCLEAR ENGINEERING AND DESIGN285   126 - 133   2015年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE SA  

    In this study, the mechanism of non-axisymmetric pipe-wall thinning that led to a pipeline break in the Mihama nuclear power plant in 2004 is evaluated in a scale-model experiment in a water tunnel having an elbow and orifice under the influence of swirling flow. The velocity fields are measured by stereo particle image velocimetry, and the mass transfer rate is measured by a benzoic acid dissolution method at Reynolds number Re = 3 x 10(4) with and without swirling flow. The non-axisymmetric swirling flow is found to be generated behind the elbow, even when the axisymmetric swirling flow is supplied in the upstream of the elbow. The secondary flow generated in the elbow is not suppressed in the pipeline 10 diameters downstream of elbow in the swirling flow, and in this flow geometry, the non-axisymmetry of the flow is greatly magnified downstream of the orifice. The measured mass transfer rates downstream of the orifice under the influence of swirling flow indicate that the Sherwood number distribution on one side of the pipe is enhanced and that on the other side is reduced owing to the appearance of the non-axisymmetric swirling flow, which results in the occurrence of non-axisymmetric pipe-wall thinning downstream of the orifice. (C) 2015 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.nucengdes.2014.12.036

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  • Three-dimensional flow structure in highly buoyant jet by scanning stereo PIV combined with POD analysis 査読

    R. Watanabe, T. Gono, T. Yamagata, N. Fujisawa

    INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW52   98 - 110   2015年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE INC  

    The flow characteristics and the structure of highly buoyant jet of low density fluid issuing into a stagnant surrounding of high density fluid is studied by scanning stereo My combined with proper orthogonal decomposition (POD) analysis. The experiment is carried out at Froude number of 0.3 and Reynolds number of 200, which satisfies the inflow condition due to the unstable density gradient near the nozzle exit. An increase in the maximum mean velocity occurs and the vertical velocity fluctuation is highly amplified near the nozzle exit, which suggests the influence of inflow due to the unstable density gradient. The POD analysis indicates that the vertical velocity fluctuation is the major source of fluctuating energy contributing to the development of the highly buoyant jet. The examination of the POD modes show that the longitudinal structure of the vertical velocity fluctuation is generated along the jet axis having the opposite sign of velocity fluctuation on both sides of the jet axis. The vertical scale of the POD mode decreases with increasing the mode number and results in the frequent appearance of cross-flow across the buoyant jet. The reconstruction flow from the POD modes indicates that the vortex structure is caused by the highly sheared layer between the upward and downward velocity and the inflow is induced by the vortex structure. The magnitude of the vortex structure seems to be weakened with an increase in the distance from the nozzle and the buoyant jet approaches to an asymptotic state in the further downstream. (C) 2014 Elsevier Inc. All rights reserved.

    DOI: 10.1016/j.ijheatfluidflow.2014.12.003

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  • Measurement of Three-Dimensional Temperature Field of Flickering Premixed Flame with and without Coflow 査読

    N. Fujisawa, J. Yamada, T. Yamagata

    FLOW TURBULENCE AND COMBUSTION93 ( 4 ) 723 - 739   2014年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER  

    The three-dimensional (3D) temperature field of the flickering flame with and without coflow can be measured using the flame reaction technique combined with tomographic reconstruction. This combined experimental technique facilitates the non-intrusive measurement of the unsteady 3D temperature field of a premixed methane/air flame. The target flame visualization, which was achieved by the flame reaction of sodium in the supplied mists of sodium chloride solution and line-of-sight intensity images of the flame, was transformed into the temperature field using calibration with the sodium D-line reversal method combined with imaging from six CCD cameras located around the flame. The uncertainty in tomographic temperature measurement was confirmed for the steady axisymmetric flame under the influence of strong coflow. Tomographic temperature measurements were applied to the flickering flame with and without coflow, and the results were analyzed using proper orthogonal decomposition (POD) to understand the unsteady behavior of the temperature field of the flickering flame. The flickering energy was found to be dominant in the first two POD modes. Flame flickering with and without coflow was found to be dominant in the axisymmetric and non-axisymmetric modes, respectively. The characteristics of the flickering flame with and without coflow are discussed in this paper, based on spectrum analysis. The results suggest that the structure of the flickering flame is highly modified by the presence of even a small magnitude of coflow.

    DOI: 10.1007/s10494-014-9568-y

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  • Measurement of Aerodynamic Sound Source around a Circular Cylinder by Particle Image Velocimetry 査読

    Yasuyuki Oguma, Takayuki Yamagata, Nobuyuki Fujisawa

    Journal of Flow Control, Measurement & Visualization2 ( 3 ) 105 - 109   2014年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

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  • Flickering characteristics and temperature field of premixed methane/air flame under the influence of co-flow 査読

    Nobuyuki Fujisawa, Takao Abe, Takayuki Yamagata, Hirofumi Tomidokoro

    ENERGY CONVERSION AND MANAGEMENT78   374 - 385   2014年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The flickering characteristics and the temperature field of an axisymmetric premixed methane/air flame under the influence of co-flow are studied experimentally using the image analysis and the flame reaction technique. The premixed flame is visualized by the alkali metal solution of sodium (Na) for characterizing the flickering characteristics. The temperature measurement of the flame is carried out using the flame reaction technique combined with the relationship between the local intensity of the flame and the temperature from the sodium D-line reversal method, and the influence of the number density distribution of Na on the measured temperature field is corrected by the measurement integrated analysis of the flame with the iterative procedure. This technique is validated by the local temperature measurement in the steady flame under the influence of co-flow using the thermocouple calibrated by the sodium D-line reversal method. The flame visualization and temperature measurement in the flickering flame of the premixed methane/air flame indicates that the flame contour and the temperature field oscillate periodically with the flickering frequency due to the Kelvin-Helmholtz instability of the flame. The oscillation amplitude decreases and the frequency increases gradually with the co-flow velocity increases similar to the observation in the diffusion flame in literature, while the oscillation amplitude grows with the equivalence ratio increases. These changes in the flickering characteristics of the flame are caused by the variations of the temperature field in the premixed flame. (C) 2013 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.enconman.2013.10.059

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  • Visualization of Special Features in “The Tale of Genji” by Text Mining and Correspondence Analysis with Clustering 査読

    Hisako Hosoi, Takayuki Yamagata, Yuya Ikarashi, Nobuyuki Fujisawa

    Journal of Flow Control, Measurement & Visualization2 ( 1 ) 1 - 6   2014年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

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  • Experimental and numerical studies on mass transfer characteristics behind an orifice in a circular pipe for application to pipe-wall thinning 査読

    Takayuki Yamagata, Akihiro Ito, Yuki Sato, Nobuyuki Fujisawa

    EXPERIMENTAL THERMAL AND FLUID SCIENCE52   239 - 247   2014年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE INC  

    Experimental and numerical studies are carried out to understand the mass transfer characteristics in a circular pipe behind an orifice, which is often encountered in pipe-wall thinning due to flow accelerated corrosion in pipelines of nuclear/fossil power plants. The measurement of mass transfer coefficient is conducted by using benzoic acid dissolution method in a water flow, which allows the measurement of mass transfer behind the orifice in a circular pipe at the Schmidt number near the actual operating condition of the pipeline. The measurement of mass transfer coefficient behind the orifice shows a maximum Sherwood number in the region 1-2 pipe diameters downstream of the orifice due to the flow turbulence, and it decreases gradually in the downstream, which agrees qualitatively with the feature of pipe-wall thinning in the pipeline in literature. The present result indicates that the Sherwood number behind the orifice is greatly increased by increasing the Schmidt number and the Reynolds number, though the geometrical factor, which is the ratio of the thinning rate of the orifice flow with respect to that of the fully developed pipe flow, is weakly dependent of these parameters. It is also found that the experimental Sherwood number profiles and the mean velocity distribution behind the orifice are well reproduced in the numerical simulation by the k-epsilon model with the empirical modification of high-Schmidt-number flows, though the maximum Sherwood number is slightly overpredicted, reflecting the higher prediction of turbulence energy behind the orifice. These results demonstrate the usefulness of the numerical simulation for predicting the pipe-wall thinning due to the flow accelerated corrosion in the orifice flow. (C) 2013 Elsevier Inc. All rights reserved.

    DOI: 10.1016/j.expthermflusci.2013.09.017

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  • The effect of liquid film on liquid droplet impingement erosion 査読

    Nobuyuki Fujisawa, Takayuki Yamagata, Kengo Saito, Kanto Hayashi

    NUCLEAR ENGINEERING AND DESIGN265   909 - 917   2013年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE SA  

    In the present paper, the pipe-wall thinning due to liquid droplet impingement erosion is studied experimentally by using a high-speed conical spray under the influences of liquid film on the target specimen. The size of the droplets considered is an order of tens of micrometers in diameter, which is the same order as those expected in the pipeline of nuclear/fossil power plants. In order to evaluate the erosion rate by the liquid droplet impingement under the influence of liquid film, the experiments are conducted by various combinations of the specimen diameters and the standoff distances of the spray from the nozzle. The experimental results show that the erosion depth increases linearly with the local flow volume, indicating the presence of terminal stage of erosion. The present results indicate that the erosion rate increases with decreasing the specimen diameter and increases slightly with increasing the standoff distance. This result combined with the theoretical consideration of the liquid film on the specimen leads to the conclusion that the erosion rate increases with decreasing the liquid film thickness, which supports the numerical result of liquid droplet impingement erosion in literature. Then, the erosion model for predicting the erosion rate by the liquid droplet impingement is proposed considering the influence of the liquid film. (C) 2013 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.nucengdes.2013.07.039

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  • Evaluation of Flight Trajectory and Unsteady Fluid Forces on Kicked Non-Spinning Soccer Ball by Digital Image Analysis 査読

    Takayuki Yamagata, Takuya Nagasawa, Nobuyuki Fujisawa, Takeshi Asai

    Journal of Flow Control, Measurement & Visualization1 ( 3 ) 86 - 93   2013年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

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  • Measurement of sound source distribution around a circular cylinder in a uniform flow by combined particle image velocimetry and microphone technique 査読

    Y. Oguma, T. Yamagata, N. Fujisawa

    Journal of Wind Engineering and Industrial Aerodynamics118   1 - 11   2013年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    This study examined an experimental method for locating aerodynamic sound sources from a bluff body in a stream. The sound sources are evaluated from cross-correlation analysis of the pressure fluctuations on and around the flow field and the sound pressure fluctuations. Measurements are carried out in the sound field emitted from the circular cylinder at Reynolds number Re=4×104. The pressure fluctuations around the circular cylinder are evaluated by measuring the instantaneous velocity field using particle image velocimetry combined with the pressure Poisson equation, while the sound pressure fluctuations are measured simultaneously by a microphone in the far field. The experimental results showed that sound sources were found near the flow separation on both sides of the cylinder and in the near wake. The experimental results were validated by direct measurement of the pressure fluctuations on the cylinder surface using a pressure transducer. The sound sources obtained from the cross-correlation analysis agreed well with those of the direct measurement of pressure fluctuations on the cylinder surface and those around the cylinder in previous studies. © 2013 Elsevier Ltd.

    DOI: 10.1016/j.jweia.2013.04.003

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  • Non-Axisymmetric Mass Transfer Phenomenon behind an Orifice in a Curved Swirling Flow 査読

    Tsuyoshi Takano, Takayuki Yamagata, Yuki Sato, Nobuyuki Fujisawa

    Journal of Flow Control, Measurement & Visualization1 ( 1 ) 1 - 5   2013年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

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  • The mechanism of asymmetric pipe-wall thinning behind an orifice by combined effect of swirling flow and orifice bias 査読

    Nobuyuki Fujisawa, Takayuki Yamagata, Syo Kanno, Akihiro Ito, Tsuyoshi Takano

    NUCLEAR ENGINEERING AND DESIGN252   19 - 26   2012年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE SA  

    In this paper, the mechanism of asymmetric pipe-wall thinning caused by flow accelerated corrosion behind an orifice in a circular pipe is studied by measuring the velocity fields by PIV and the mass transfer coefficients by naphthalene sublimation method. An attention is placed on the variations of the velocity fields and mass flux under the combined effect of swirling flow and orifice bias. The present measurement indicates that the flow field become asymmetric about the pipe axis due to the influence of swirling flow at large swirl intensity S = 0.3 in combination with an allowable orifice bias as small as 0.8% of a pipe diameter of standard steel pipes. This flow phenomenon results in the asymmetric distribution of mass transfer coefficient along the pipe-wall behind the orifice. The position of enhanced mass transfer occurs on the shorter orifice side near the orifice due to the flow reattachment, while the flow on the longer orifice side remains the same distribution of mass transfer coefficient as the case without swirl. These variations of velocity field and mass transfer data suggest that the mechanism of asymmetric pipe-wall thinning behind the orifice is due to the combined effect of swirling flow and orifice bias. (c) 2012 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.nucengdes.2012.07.001

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  • Experiments on liquid droplet impingement erosion by high-speed spray 査読

    Nobuyuki Fujisawa, Takayuki Yamagata, Kanto Hayashi, Tsuyoshi Takano

    NUCLEAR ENGINEERING AND DESIGN250   101 - 107   2012年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE SA  

    In the present paper, liquid droplet impingement erosion is studied by using a high-speed spray. This experiment allows the evaluation of erosion rate of solid materials due to the impingement of liquid droplets having an order of tens of micrometer in diameter, which corresponds to those of actual conditions in nuclear power plants. The droplet properties are characterized by measuring the droplet velocity by particle image velocimetry, the diameter by shadowgraph and the number of impinging droplets in a unit area by sampling probe. The erosion rate of aluminum material by water droplets is tested by the high-speed spray in some combinations of the distances from the nozzle and droplet velocities. Although the experimental erosion rate in the far field of the nozzle is reproduced by the theoretical erosion model, the erosion rate in the near field does not. This suggests the damping effect of liquid film over the test specimen in the near field. The experimental result also indicates that the erosion rate increases in proportional to the power of 7.0 of droplet velocity in the maximum rate stage. The result indicates a certain degree of deviation from the previous experiment in literature, which may suggest the influence of the droplet diameter and the liquid film on the liquid droplet impingement erosion. (C) 2012 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.nucengdes.2012.06.022

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  • Critical consideration on wall thinning rate by liquid droplet impingement erosion 招待 査読

    Nobuyuki Fujisawa, Ryo Morita, Akira Nakamura, Takayuki Yamagata

    E-Journal of Advanced Maintenance4 ( 2 ) 79 - 87   2012年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

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  • Mass transfer measurements behind an orifice in a circular pipe flow for various combinations of swirl intensity and orifice bias 査読

    Tsuyoshi Takano, Takayuki Yamagata, Akihiro Ito, Nobuyuki Fujisawa

    Journal of Power and Energy Systems6 ( 3 ) 402 - 411   2012年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1299/jpes.6.402

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  • Time-resolved scanning stereo PIV measurement of three-dimensional velocity field of highly buoyant jet 査読

    T. Gono, T. Syuto, T. Yamagata, N. Fujisawa

    JOURNAL OF VISUALIZATION15 ( 3 ) 231 - 240   2012年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER  

    The time-resolved scanning stereo PIV system, which consists of a CW Nd:YAG laser, two high-speed CMOS cameras, a Galvano mirror and a pulse controller, is developed for time-sequential three-dimensional velocity field measurement of liquid flow. This experimental technique is validated by the measurement of a laminar non-buoyant jet, and is applied to the 3D velocity measurement of a highly buoyant jet at Froude number 0.3 and Reynolds number 200, which satisfy the inflow condition due to the unstable density gradient. The measurement of statistical properties of velocity field shows the growth of turbulence intensities near the nozzle exit, which indicates the presence of inflow motion near the nozzle exit due to the unstable density gradient. The vorticity contours about the horizontal axis shows the presence of counter-rotating vortices on both sides of the jet centerline, while the vorticity contour about the vertical axis indicates the presence of spiral growth of a pair of vortices along the jet centerline. The growth of the spiral structure along the jet centerline is recognized in the iso-vorticity contours obtained from the time-resolved measurement of 3D velocity field.

    DOI: 10.1007/s12650-012-0129-y

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  • Characteristics of Liquid Droplet Impingement Erosion of Carbon Steel with and without Oxide Film 査読

    Tsuyoshi Takano, Takayuki Yamagata, Akiharu Ikarashi, Nobuyuki Fujisawa

    Visualization of Mechanical Processes2 ( 2 )   2012年5月

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  • Quantitative visualization of temperature field in non-luminous flame by flame reaction technique 査読

    M. Ohkubo, Y. Nakagawa, T. Yamagata, N. Fujisawa

    JOURNAL OF VISUALIZATION15 ( 2 ) 101 - 108   2012年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER  

    An experimental technique for measuring a temperature field in an axisymmetric non-luminous flame is developed using the flame reaction technique combined with the inverse Abel transformation. Flame visualization is carried out using alkali metal solution of Potassium (K), which is supplied to a premixed methane/air flame in a form of spray mist. The basic principle of this technique is based on the measurement of local emission intensity distribution visualized by the flame reaction, which is a function of temperature according to the Maxwell-Boltzmann statistics of thermodynamics. The relationship between the local intensity and the temperature is obtained from the calibration study, in which the local intensity is evaluated from the line of sight intensity by the inverse Abel transformation, and the temperature is measured by thermocouple. This technique is successfully applied to the measurement of local temperature distribution in steady and flickering premixed methane/air flame. The temperature field in the flickering flame indicates that the local temperature oscillates periodically with the flickering frequency, and the highest temperature is found along the flame front and in the merging region.

    DOI: 10.1007/s12650-011-0109-7

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  • Experimental and numerical study on onset of inflow in near field of buoyant jet at low Froude number 査読

    T. Maeda, N. Fujisawa, T. Syuto, T. Yamagata

    JOURNAL OF VISUALIZATION15 ( 1 ) 67 - 75   2012年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER  

    In the present paper, the onset of inflow in the near field of a vertical buoyant jet issuing from a square duct is studied by experimental flow visualization and numerical simulation. The experimental critical condition for the onset of inflow is obtained from the scanning LIF visualization in the near field of the buoyant jet at various combinations of Froude numbers and Reynolds numbers. The experimental result shows that the critical Froude number increases with an increase in Reynolds number of the buoyant jet. The critical condition is also examined by numerical simulation based on the Navier-Stokes equation and energy conservation equation, under the assumption that the flow separation occurs at the duct exit. The main feature of the inflow observed by experiment is well reproduced in the numerical results.

    DOI: 10.1007/s12650-011-0104-z

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  • EXPERIMENTAL STUDY ON LIQUID DROPLET IMPINGEMENT EROSION BY UNIFORMLY SPRAYED DROPLETS 査読

    Nobuyuki Fujisawa, Kanto Hayashi, Daichi Hama, Takayuki Yamagata, Tsuyoshi Takano

    PROCEEDINGS OF THE 20TH INTERNATIONAL CONFERENCE ON NUCLEAR ENGINEERING AND THE ASME 2012 POWER CONFERENCE - 2012, VOL 1   169 - 174   2012年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:AMER SOC MECHANICAL ENGINEERS  

    In the present paper, the characteristics of liquid droplet impingement erosion are studied experimentally to propose a new model for predicting the pipe-wall thinning The spray droplets used in this study is an order of tens of micrometers in diameter. In order to obtain an accurate estimation of erosion rate, an experiment is carried out under the condition of the circular specimen in uniformly sprayed droplets. The experiments on erosion rate indicate that the wall thinning increases linearly with respect to the local droplet volume, which is measured by the sampling probe. It is found that the erosion rate is proportional to the power of 4.0 with respect to the local flow rate of the droplets. This power number is found to be equivalent to 7.2 for the droplet velocity. The present experiment also showed the influence of the liquid film on the erosion, which reduces the erosion rate of the material.

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  • EXPERIMENT AND NUMERICAL SIMULATION OF ASYMMETRIC PIPE WALL THINNING BEHIND AN ORIFICE BY COMBINED EFFECT OF SWIRLING FLOW AND ORIFICE BIAS 査読

    Takayuki Yamagata, Yuki Sato, Akihiro Ito, Tsuyoshi Takano, Nobuyuki Fujisawa

    PROCEEDINGS OF THE 20TH INTERNATIONAL CONFERENCE ON NUCLEAR ENGINEERING AND THE ASME 2012 POWER CONFERENCE - 2012, VOL 1   161 - 167   2012年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:AMER SOC MECHANICAL ENGINEERS  

    In this paper, combined influence of swirling flows and orifice biases is investigated by a mass transfer experiment and a numerical simulation. In the mass transfer experiment, pipe wall thinning behind an orifice in a circular pipe is evaluated with benzoic acid instead of steel. In addition, a numerical simulation for velocity and concentration fields is performed to estimate mass transfer behind the orifice. The numerical simulation using the standard k-epsilon model of turbulence well reproduces the distributions of Keller coefficient behind the orifice, which agree with those of the experiment in no-swirling flows. Experimental results show asymmetric pipe wall thinning is occurred under combined influence of a swirling flow and a slight orifice bias, while a symmetric pipe wall thinning is seen in the no-swirling flows even with the orifice bias.

    DOI: 10.1115/ICONE20-POWER2012-54681

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  • ON THE INFLOW PHENOMENON IN NEAR FIELD OF BUOYANT JET AT LOW FROUDE NUMBER 査読

    Atsushi Maeda, Takayuki Yamagata, Nobuyuki Fujisawa

    PROCEEDINGS OF THE 20TH INTERNATIONAL CONFERENCE ON NUCLEAR ENGINEERING AND THE ASME 2012 POWER CONFERENCE - 2012, VOL 5   609 - 613   2012年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:AMER SOC MECHANICAL ENGINEERS  

    In the present paper, the inflow phenomenon in the near-field of a buoyant jet issuing from a square duct is studied by using scanning LIP and scanning Ply measurements. The scanning LIF visualization allows an insight into the critical condition of the inflow phenomenon in a wide range of Froude number and Reynolds number. While, the scanning PIV allows the quantitative information on the inflow rate through the duct exit. The experimental result shows that the critical Froude number increases with an increase in Reynolds number in the duct exit up to Reynolds number 2,000, though it is weakened at higher Reynolds number. The examination of the inflow rate indicates that the large magnitude of the inflow rate occurs in the lower Froude number and Reynolds number.

    DOI: 10.1115/ICONE20-POWER2012-55245

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  • 押出し金型における粘弾性流体の分配室からスロットへの縮小流れにおける圧力損失 査読

    穴澤朝彦, 津田武明, 吉羽洋, 鳴海敬倫, 藤澤延行, 山縣貴幸, 長谷川富市

    日本レオロジー学会誌40 ( 2 ) 91 - 99   2012年

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1678/rheology.40.91

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  • Effect of Contraction Width on the Vortex Formation of Viscoelastic Flow in Asymmetric Planar Contractions 査読

    Takayuki Yamagata, Takahiro Yajima, Nobuyuki Fujisawa

    Journal of Fluid Science and Technology6 ( 6 ) 1011 - 1020   2011年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1299/jfst.6.1011

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  • 流動加速腐食による配管減肉に関する研究(旋回流とオリフィス偏心の組み合わせ効果による非対称流の発生) 査読

    大久保雅一, 山縣貴幸, 菅野翔, 藤澤延行

    日本機械学会論文集 B編(Web)77 ( 774 ) 386-394 (WEB ONLY) - 394   2011年12月

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

    The flow accelerated corrosion in a pipe is an important topic of interest associated with pipe-wall thinning phenomenon in a highly aged nuclear power plant. In the present study, the velocity field behind an orifice in a pipe is studied by PIV measurement in some combinations of swirl flow magnitudes and orifice bias. The flow observations along the flow axis and across the pipe indicate that the effect of orifice bias is not so influential on the flow behavior behind the orifice at small swirl flow magnitude. However, the asymmetrical flow pattern is observed in the flow behind the orifice at large swirl flow magnitude. The accelerated flow behind the orifice reattaches on the pipe wall of shorter orifice height and the corresponding velocity fluctuation decreases at large swirl flow magnitude, which occurs even at the small orifice bias of 0.7% of pipe diameter. This phenomenon is expected to promote the asymmetrical distribution of pipe-wall thickness due to flow accelerated corrosion in a prototype pipe flow. © 2011 The Japan Society of Mechanical Engineers.

    DOI: 10.1299/kikaib.77.386

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  • 高速噴霧流による液滴衝撃エロージョン実験と液滴パラメータの光学計測 査読

    Akiharu Ikarashi, Takayuki Yamagata, Daichi Hama, Tsuyoshi Takano, Nobuyuki Fujisawa

    可視化情報学会論文集31 ( 11 ) 63 - 67   2011年11月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:社団法人 可視化情報学会  

    原子力発電プラントの配管減肉の一要因である液滴衝撃エロージョン現象の解明を目的として,高速噴霧流を用いた液滴衝撃エロージョン実験を行った.本論文では,液滴パラメータである速度,液滴径,液滴の衝突数を,それぞれ,PIV, シャドーグラフ法,レーザー光減衰法によって計測する方法を示し,さらに,高速噴霧流の液滴パラメータの計測結果,ステンレス材料のエロージョン実験結果を示した.本実験結果によると,高速噴霧流装置で発生した実機の推定液滴径(数十μm)によって液滴衝撃エロージョンが発生し,減肉したステンレス材料表面には梨地状の凹凸パターンが観測された.ただし、減肉痕の大きさは数百μmオーダーであり、衝突する液滴径よりかなり大きい.

    DOI: 10.3154/tvsj.31.63

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  • 流動加速腐食による配管減肉に関する研究--旋回流とオリフィス偏心の組み合わせ効果による物質輸送現象 査読

    高野 剛, 山縣 貴幸, 伊藤 嘉人

    保全学10 ( 2 ) 30 - 35   2011年7月

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    記述言語:日本語   出版者・発行元:日本保全学会  

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  • 液滴衝撃エロージョンに関する研究--高速噴霧流による減肉特性の評価 査読

    濱 大地, 山縣 貴幸, 高野 剛

    保全学10 ( 2 ) 36 - 41   2011年7月

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    記述言語:日本語   出版者・発行元:日本保全学会  

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  • Occurrence of asymmetrical flow pattern behind an orifice in a circular pipe 査読

    M. Ohkubo, S. Kanno, T. Yamagata, T. Takano, N. Fujisawa

    JOURNAL OF VISUALIZATION14 ( 1 ) 15 - 17   2011年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER  

    DOI: 10.1007/s12650-010-0058-6

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  • Investigation on pipe-wall thinning by flow accelerated corrosion (occurrence of asymmetrical flow by combined effect of swirling flow and orifice bias) 査読

    Masakazu Ohkubo, Takayuki Yamagata, Syo Kanno, Nobuyuki Fujisawa

    Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B77 ( 774 ) 386 - 394   2011年

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    The flow accelerated corrosion in a pipe is an important topic of interest associated with pipe-wall thinning phenomenon in a highly aged nuclear power plant. In the present study, the velocity field behind an orifice in a pipe is studied by PIV measurement in some combinations of swirl flow magnitudes and orifice bias. The flow observations along the flow axis and across the pipe indicate that the effect of orifice bias is not so influential on the flow behavior behind the orifice at small swirl flow magnitude. However, the asymmetrical flow pattern is observed in the flow behind the orifice at large swirl flow magnitude. The accelerated flow behind the orifice reattaches on the pipe wall of shorter orifice height and the corresponding velocity fluctuation decreases at large swirl flow magnitude, which occurs even at the small orifice bias of 0.7% of pipe diameter. This phenomenon is expected to promote the asymmetrical distribution of pipe-wall thickness due to flow accelerated corrosion in a prototype pipe flow. © 2011 The Japan Society of Mechanical Engineers.

    DOI: 10.1299/kikaib.77.386

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  • Simultaneous visualization of temperature and velocity fields of flickering flame by combined flame reaction and PIV 査読

    M. Ohkubo, T. Abe, T. Yamagata, N. Fujisawa

    Journal of Flow Visualization and Image Processing18 ( 3 ) 241 - 251   2011年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    In this paper, simultaneous visualization technique for temperature and velocity fields of a premixed methane air flame is described. The temperature field is visualized by the flame reaction of potassium combined with inverse Abel transformation, while the velocity field of the flame is simultaneously measured by particle image velocimetry (PIV). This new experimental technique allows an insight into the structure of temperature and velocity fields of the flickering flame. It is found that the temperature and the velocity fields in the flickering flame indicate nonlinear oscillation of the flame. During the flame flickering, the temperature in the flame fronts increases to the highest temperature in the merging region, which is followed by the entrainment of the surrounding air into the flame. This fluid motion contributes to the decrease in temperature and self-sustained oscillation of the flame. © 2011 by Begell House, Inc.

    DOI: 10.1615/JFlowVisImageProc.2012003801

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  • Flow visualization and scanning PIV measurement of three-dimensional structure in near field of strongly buoyant jet 査読

    T. Syuto, N. Fujisawa, T. Takasugi, T. Yamagata

    JOURNAL OF VISUALIZATION13 ( 3 ) 203 - 211   2010年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER  

    The near-field structure of strongly buoyant jet issuing from a square nozzle at low Froude and Reynolds numbers is studied by using LIF flow visualization and time-resolved scanning PIV. These experimental techniques allow the visualization of unsteady three-dimensional flow phenomenon occurring in the near-field of strongly buoyant jet. It is found that the buoyant jet is unstable to the positive buoyancy forces, which promote the inflow motion near the nozzle exit. The surrounding low temperature fluid moves into the nozzle inside along the nozzle corner and mixes with the high temperature fluid deep into the nozzle. Then, the flow pattern inside the nozzle becomes highly complex to promote the laminar to turbulent transition of the jet. The statistical flow characteristics of the strongly buoyant jet are evaluated from the scanning PIV measurement, and the result indicates the presence of axisymmetric distributions of mean flow and velocity fluctuations in the circle of diameter equal to the square side of the nozzle.

    DOI: 10.1007/s12650-010-0027-0

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  • Vortex formation in a viscoelastic entry flow of asymmetric planar contraction 査読

    T. Anazawa, N. Fujisawa, T. Yajima, T. Yamagata

    JOURNAL OF VISUALIZATION13 ( 3 ) 191 - 193   2010年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER  

    DOI: 10.1007/s12650-010-0028-z

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  • Understanding Key Parameters in Flow Accelerated Corrosion for Advanced Wall Thinning Prediction 査読

    Hiroshi Abe, Shinji Ebara, Nobuyuki Fujisawa, Hidetoshi Hashizume, Kiwamu Sue, Yutaka Watanabe, Takayuki Yamagata

    Proceedings of International Symposium on the Ageing Management and Maintenance of Nuclear Power Plants (ISaG2010)   38 - 46   2010年5月

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  • 物体周りの3次元非定常流の計測融合シミュレーション

    山縣 貴幸

    東北大学   2009年3月

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    記述言語:英語   掲載種別:学位論文(博士)  

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  • Reproduction of Three-Dimensional Flow with Karman Vortex Street by Integrating Flow Simulation and Pressure Measurement

    Takayuki Yamagata, Toshiyuki Hayase

    Proceedings of Eighth International Symposium on Advanced Fluid Information and Transdisciplinary Fluid Integration   50 - 51   2008年12月

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  • Measurement-Integrated Simulation of Three-Dimensional Flow Behind a Square Cylinder Using Pressure Measurement on the Cylinder

    Takayuki Yamagata, Toshiyuki Hayase

    Bulletin of the Americal Physical Society53 ( 15 ) 36 - 37   2008年11月

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • Estimation of Unsteady Blood Flow Rate in Ultrasonic-Measurement-Integrated Simulation -Effect of Estimation Precision on Reproducibility of Blood Flow

    Takayuki Yamagata, Toshiyuki Hayase

    International Symposium on Nano-Biomedical Engineering, 7th International Symposium of 2007 Tohoku University Global COE Program “Global Nano-Biomedical Engineering Education and Research Network Centre   36 - 37   2008年10月

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  • Effect of Feedback Data Rate in PIV Measurement-Integrated Simulation 査読

    Takayuki Yamagata, Toshiyuki Hayase, Hiroshi Higuchi

    Journal of Fluid Science and Technology3 ( 4 ) 477 - 487   2008年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1299/jfst.3.477

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  • ハイブリッド風洞による角柱後流のカルマン渦列の非定常圧力場の再現 査読

    山縣貴幸, 柴田光, 早瀬敏幸, SMIT Kasper

    日本機械学会論文集 B編74 ( 738 ) 362 - 369   2008年2月

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

    This paper deals with the hybrid wind tunnel which combines wind tunnel experiment and numerical simulation to obtain the exact and detailed information of real flows. The hybrid wind tunnel, which is based on the observer theory, utilizes partial pressure measurement of a real flow for the numerical simulation. The measured pressure is included by the simulation through a feedback loop to overcome the difficulty of specifying exact boundary or initial conditions as well as the effect of modeling error. In this paper, the reproducibility of a pressure field on the hybrid wind tunnel, which treats a fundamental flow with the Karman vortex street behind a square cylinder, is investigated by comparison with pressure measurement on the side wall of the wind tunnel. As compared with ordinary simulation, mean pressure and pressure fluctuation reproduced by the hybrid wind tunnel agree well with that of experiment with large time steps which are inappropriate for ordinary simulations. Especially, the oscillation of the pressure synchronizes with that of experiment at -4<I>D</I>?x?3<I>D</I> (<I>D</I> : cylinder width) on the side wall of the wind tunnel, showing positive correlation with the experiment. The reduction of computational cost by using large time steps enables the hybrid wind tunnel to perform real time analysis of real flows.

    DOI: 10.1299/kikaib.74.362

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  • Effects of Number of Feedback Points in PIV Measurement-Integrated Simulation

    Takayuki Yamagata, Toshiyuki Hayase, Hiroshi Higuchi

    Proceedings of The Seventh International Symposium on Advanced Fluid Information and The Fourth International Symposium on Transdisciplinary Fluid Integration   232 - 235   2007年12月

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  • Inclined Centrifuge Microscope For Measuring Frictional Characteristics Of Red Blood Cells Moving On Glass Plate In Plasma 査読

    Toshiyuki Hayase, Hidekatsu Sugiyama, Takayuki Yamagata, Kosuke Inoue, Atsushi Shirai, Motohiro Takeda

    Proceedings of the 2005 Summer Bioengineering ConferenceCD-ROM   1 - 2   2005年6月

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  • Transdisciplinary Methodology Integrating Measurement and Simulation in Application of Complex Biomedical Flows

    Toshiyuki Hayase, Kenichi Funamoto, Takayuki Yamagata, Lei Liu, Atsushi Shirai, Makoto Ohta, Kosuke Inoue, Yoshifumi Saijo, Tomoyuki Yambe

    Proceedings of the 5th International Symposium on Advanced Fluid information (AFI-2005)   36 - 39   2005年

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  • Microscopic Observation of Red Blood Cells Moving on Glass Plate under Inclined Centrifugal Force

    Kotomi Saito, Takayuki Yamagata, Toshiyuki Hayase, Atsushi Shirai, Kosuke Inoue, Motohiro Takeda

    Frontiers of Medical Infomatics, The 4th International Simposium on Future Medical Engineering based on Bio-nanotechnology(21st Century COE Program)   86 - 87   2004年6月

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MISC

  • クロスフロー水車の性能に関する数値解析

    WANG Tianbo, 山縣 貴幸, 藤澤 延行

    北陸信越支部総会・講演会 講演論文集2018 ( 0 )   2018年

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  • D型物体周りの流れ場計測と音源分布の可視化

    中田 陽介, 山縣 貴幸, 藤澤 延行

    北陸信越支部総会・講演会 講演論文集2018 ( 0 )   2018年

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  • 90°エルボ内部の速度場のPIV計測と半径比の影響

    五十嵐 裕也, 田口 翔一, 卯野 拓, 山縣 貴幸, 藤澤 延行

    北陸信越支部総会・講演会 講演論文集2018 ( 0 )   2018年

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  • 1514 フリッカリング火炎の変動特性に及ぼす当量比と周囲流の影響(OS2-3 熱流体の可視化と計測)

    奥田 健志, 藤澤 延行, 山縣 貴幸

    北陸信越支部総会・講演会 講演論文集2016 ( 0 ) _1514 - 1_-_1514-3_   2016年

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  • 1501 流体の密度勾配によって発生する水平管出口近傍の流入現象(OS2-1 熱流体の可視化と計測)

    金子 芳樹, 藤澤 延行, 山縣 貴幸

    北陸信越支部総会・講演会 講演論文集2016 ( 0 ) _1501 - 1_-_1501-3_   2016年

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  • 1502 環状二相流条件下におけるオリフィス背後の液膜特性(OS2-1 熱流体の可視化と計測)

    鶴田 英文, 西井 悠平, 藤澤 延行, 山縣 貴幸, 稲田 文夫

    北陸信越支部総会・講演会 講演論文集2016 ( 0 ) _1502 - 1_-_1502-3_   2016年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 403 エルボ内部および下流における物質と運動量輸送の評価

    五十嵐 裕也, 田口 翔一, 山縣 貴幸, 藤澤 延行

    山梨講演会講演論文集2015 ( 0 ) 94 - 95   2015年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 402 キャビテーションジェットのシャドウグラフイメージングと圧力パルスの同時計測

    柳澤 慧太, 渡部 龍太, 山縣 貴幸, 藤澤 延行

    山梨講演会講演論文集2015 ( 0 ) 92 - 93   2015年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • A213 曲り旋回流を伴う管内オリフィス背後の物質輸送現象の非軸対称性に関する研究(OS2 保全設備診断技術(3))

    高野 剛, 内山 和哉, 山縣 貴幸, 藤澤 延行

    動力・エネルギー技術の最前線講演論文集 : シンポジウム2014 ( 0 ) 193 - 194   2014年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

    The influence of the swirling intensity on non-axisymmetric mass transfer rate behind the orifice in a curved swirling flow is investigated experimentally. The experimental results indicate that the high mass transfer rate is observed on one side of the pipe behind the orifice in a strong swirling flow, although the mass transfer rate keeps almost axisymmetric distribution in a weak swirling flow.

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  • 0606 液滴衝撃エロージョンに関する実験的研究

    藤澤 延行, 和田 慧太郎, 山縣 貴幸

    流体工学部門講演会講演論文集2014 ( 0 ) _0606 - 1_-_0606-2_   2014年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

    This paper presents an experimental study on the liquid droplet impingent erosion of aluminum material using the high-speed spray jet. The flow configuration studied is the pin-hole type erosion, which has the erosion depth comparatively larger than the spray width. The experimental result shows that the growth rate of the erosion is decreased with an increase in the erosion depth due to the influence of liquid film and their relationship is formulated.

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  • 504 硫酸カルシウムを用いた配管内の物質移動係数の計測

    内山 和哉, 山縣 貴幸, 藤澤 延行

    山梨講演会講演論文集2014 ( 0 ) 121 - 122   2014年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 505 円管内曲がり旋回流のオリフィス背後におけるステレオPIV計測

    五十嵐 裕也, 高野 剛, 山縣 貴幸, 藤澤 延行

    山梨講演会講演論文集2014 ( 0 ) 123 - 124   2014年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 506 半円状物体における空力騒音と非定常流体力に関する研究

    齋藤 希美, 山縣 貴幸, 藤澤 延行

    山梨講演会講演論文集2014 ( 0 ) 125 - 126   2014年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 306 曲がり旋回流におけるオリフィス背後の流れと物質輸送に関する数値解析(OS07-2 熱流体の可視化と計測,オーガナイズドセッション7:「熱流体の可視化と計測」)

    石塚 愛, 金谷 信明, 高野 剛, 山縣 貴幸, 藤澤 延行

    北陸信越支部総会・講演会 講演論文集2014 ( 0 ) _306 - 1_-_306-2_   2014年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 307 曲り旋回流におけるオリフィス背後の流れと物質輸送に及ぼす旋回強度の影響(OS07-2 熱流体の可視化と計測,オーガナイズドセッション7:「熱流体の可視化と計測」)

    金谷 信明, 高野 剛, 山縣 貴幸, 西宮 紹, 内山 和哉, 藤澤 延行

    北陸信越支部総会・講演会 講演論文集2014 ( 0 ) _307 - 1_-_307-2_   2014年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 310 液膜の影響を考慮した液滴衝撃エロージョンによる配管減肉予測法の開発(OS07-2 熱流体の可視化と計測,オーガナイズドセッション7:「熱流体の可視化と計測」)

    和田 慧太郎, 齋藤 健悟, 山縣 貴幸, 藤澤 延行

    北陸信越支部総会・講演会 講演論文集2014 ( 0 ) _310 - 1_-_310-2_   2014年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 302 予混合火炎におけるフリッカリングに及ぼす周囲流の影響(OS07-1 熱流体の可視化と計測,オーガナイズドセッション7:「熱流体の可視化と計測」)

    冨所 裕史, 山縣 貴幸, 藤澤 延行

    北陸信越支部総会・講演会 講演論文集2014 ( 0 ) _302 - 1_-_302-2_   2014年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 303 低フルード数浮力噴流のPOD解析(OS07-1 熱流体の可視化と計測,オーガナイズドセッション7:「熱流体の可視化と計測」)

    渡部 龍太, 山縣 貴幸, 藤澤 延行

    北陸信越支部総会・講演会 講演論文集2014 ( 0 ) _303 - 1_-_303-2_   2014年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 304 炎色反応法による予混合フリッカリング火炎の可視化とPOD解析(OS07-1 熱流体の可視化と計測,オーガナイズドセッション7:「熱流体の可視化と計測」)

    山田 淳平, 松本 陽平, 藤澤 延行, 山縣 貴幸

    北陸信越支部総会・講演会 講演論文集2014 ( 0 ) _304 - 1_-_304-2_   2014年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 312 半円柱に働く非定常流体力と空力騒音の計測に関する研究(OS07-3 熱流体の可視化と計測,オーガナイズドセッション7:「熱流体の可視化と計測」)

    KULAKIT Sangjan, 小熊 靖之, 山縣 貴幸, 藤澤 延行

    北陸信越支部総会・講演会 講演論文集2014 ( 0 ) _312 - 1_-_312-2_   2014年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 313 半円柱周りの空力騒音と流れ構造に関する実験的研究(OS07-3 熱流体の可視化と計測,オーガナイズドセッション7:「熱流体の可視化と計測」)

    小熊 靖之, 山縣 貴幸, 藤澤 延行

    北陸信越支部総会・講演会 講演論文集2014 ( 0 ) _313 - 1_-_313-2_   2014年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 1509 流れ加速型腐食におけるシュミット数に関する考察(OS03-2 熱・流体の可視化と計測,オーガナイズドセッション 3:「熱・流体の可視化と計測」)

    金沢 知之, 伊藤 晃宏, 山縣 貴幸, 藤澤 延行, 藤原 和俊, 稲田 文夫

    北陸信越支部総会・講演会 講演論文集2013 ( 0 ) 150901 - 150902   2013年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 1501 周囲流による燃焼火炎のフリッカリング現象の制御に関する研究(OS03-1 熱・流体の可視化と計測,オーガナイズドセッション 3:「熱・流体の可視化と計測」)

    冨所 裕史, 安部 貴雄, 山縣 貴幸, 藤澤 延行

    北陸信越支部総会・講演会 講演論文集2013 ( 0 ) 150101 - 150102   2013年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 1503 スキャニングステレオPIV による低フルード数浮力噴流の特異流入現象の3次元速度場計測(OS03-1 熱・流体の可視化と計測,オーガナイズドセッション 3:「熱・流体の可視化と計測」)

    前田 篤志, 石塚 愛, 渡部 龍太, 山縣 貴幸, 藤澤 延行

    北陸信越支部総会・講演会 講演論文集2013 ( 0 ) 150301 - 150302   2013年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 203 半円柱周りの空力騒音と流れ場構造に関する実験的研究(流体工学I,学術講演)

    小熊 靖之, KULAKIT Sangjan, 斎藤 希美, 山縣 貴幸, 藤澤 延行

    山梨講演会講演論文集2013 ( 0 ) 34 - 35   2013年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 256 POD解析を用いた低フルード数浮力噴流の組織構造の解明(流体工学IV,学術講演)

    渡部 龍太, 郷野 達也, 山縣 貴幸, 藤澤 延行

    山梨講演会講演論文集2013 ( 0 ) 58 - 59   2013年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 603 液膜の影響を考慮した液滴衝撃エローションによる配管減肉予測法の開発(応用熱工学I,オーガナイズドセッション,学術講演)

    和田 慧太郎, 斎藤 健悟, 山縣 貴幸, 藤澤 延行

    山梨講演会講演論文集2013 ( 0 ) 156 - 157   2013年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 時系列スキャニングステレオPIVによる低フルード数浮力噴流の三次元速度場計測(受賞論文要約)

    郷野 達也, 首藤 智明, 山縣 貴幸, 藤澤 延行

    新潟大学工学部研究報告 = 新潟大学工学部研究報告 ( 61 ) 1 - 1   2012年3月

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    記述言語:日本語   出版者・発行元:新潟大学工学部  

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  • F081003 配管減肉管理に関する最新技術知見 : (3)液滴衝撃エロージョン(LDI)の新知見

    藤澤 延行, 森田 良, 中村 晶, 山縣 貴幸

    年次大会2012 ( 0 ) _F081003 - 1-_F081003-3   2012年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

    This paper describes the critical consideration on the past studies in literature related to the wall thinning rate of the metal materials due to the liquid droplet impingement erosion. It is found that the power index of droplet velocity on the wall thinning rate ranges from 6 to 8 for the water jet and spray tests, while that of the rotating disk test shows smaller power index 5.8 which is closer to the theoretical value 5. The difference in the power indices is expected due to the influence of liquid film over the test specimen.

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  • 0504 曲がり管と旋回流の組み合わせによるオリフィス背後の配管減肉に関する研究(OS03-1 熱・流体の可視化と計測,オーガナイズドセッション 3:「熱・流体の可視化と計測」)

    菅野 翔, 山縣 貴幸, 藤澤 延行, 高野 剛

    北陸信越支部総会・講演会 講演論文集2012 ( 0 ) 50401 - 50402   2012年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 0509 PIV を用いた自由振動円柱周りの流体力の計測(OS03-2 熱・流体の可視化と計測,オーガナイズドセッション 3:「熱・流体の可視化と計測」)

    松井 俊文, 山縣 貴幸, 藤澤 延行, 長澤 拓哉

    北陸信越支部総会・講演会 講演論文集2012 ( 0 ) 50901 - 50902   2012年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 0510 スキャニング LIF/PIV による低フルード数浮力噴流の流入現象に関する研究(OS03-2 熱・流体の可視化と計測,オーガナイズドセッション 3:「熱・流体の可視化と計測」)

    前田 篤志, 藤澤 延行, 村田 一生, 山縣 貴幸

    北陸信越支部総会・講演会 講演論文集2012 ( 0 ) 51001 - 51002   2012年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 0511 2色法と PIV を用いた予混合火炎の温度・速度同時計測法に関する研究(OS03-2 熱・流体の可視化と計測,オーガナイズドセッション 3:「熱・流体の可視化と計測」)

    鹿岡 喬夫, 藤澤 延行, 富所 裕史, 山縣 貴幸

    北陸信越支部総会・講演会 講演論文集2012 ( 0 ) 51101 - 51102   2012年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 602 曲がり旋回流によるオリフィス背後の非軸対称配管減肉の数値計算(応用熱工学I,オーガナイズドセッション,学術講演)

    岩田 耕史郎, 山縣 貴幸, 藤澤 延行

    山梨講演会講演論文集2012 ( 0 ) 150 - 151   2012年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 603 高速噴霧流実験による液滴衝撃エロージョンの評価と減肉モデルの提案(応用熱工学I,オーガナイズドセッション,学術講演)

    斎藤 健悟, 林 貫人, 山縣 貴幸, 藤澤 延行

    山梨講演会講演論文集2012 ( 0 ) 152 - 153   2012年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 608 炎色反応法を用いた火炎の非接触温度計測の高度化に関する研究(応用熱工学II,オーガナイズドセッション,学術講演)

    安部 貴雄, 冨所 裕史, 山縣 貴幸, 藤澤 延行

    山梨講演会講演論文集2012 ( 0 ) 162 - 163   2012年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 305 スキャニングステレオPIVによる浮力噴流の5次元速度場の同時計測(OS5-1熱流体の可視化と計測)

    首藤 智明, 郷野 達也, 藤澤 延行, 山縣 貴幸

    北陸信越支部総会・講演会 講演論文集2011 ( 0 ) 81 - 82   2011年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 304 PIV計測に基づく円柱に作用する流体力計測に関する研究(OS5-1熱流体の可視化と計測)

    岡宮 正芳, 山縣 貴幸, 松井 俊文, 藤澤 延行

    北陸信越支部総会・講演会 講演論文集2011 ( 0 ) 79 - 80   2011年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 912 偏心を有する円管内オリフィス背後の物質輸送係数の評価 : 旋回流の影響(OS12-(2)オーガナイズドセッション《流体工学・熱流体》)

    伊藤 嘉人, 山縣 貴幸, 藤澤 延行, 高野 剛

    茨城講演会講演論文集2010 ( 0 ) 261 - 262   2010年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

    In the present paper, the mass transfer phenomenon behind an orifice in a pipe flow is studied by measuring the mass transfer coefficient along the pipe wall using naphthalene sublimation method. An attention is placed on the asymmetrical pipe-wall thinning behind an orifice under the influence of swirling-flow intensity and allowable orifice bias. The present measurement indicates that the mass transfer coefficient becomes asymmetric about the pipe axis by the combined effect of swirling flow and allowable orifice bias. It is found that the enhancement of mass transfer coefficient is observed on the shorter side of the orifice plate and the reduction is found on the opposite side. This phenomenon is found to be consistent with the flow-field observation in the previous study.

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  • E143 炎色反応による燃焼火炎の非接触温度計測(OS-12:次世代の燃焼技術(IV))

    中川 優, 大久保 雅一, 藤澤 延行, 山縣 貴幸

    熱工学コンファレンス講演論文集2010 ( 0 ) 147 - 148   2010年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

    In the present paper, an experimental technique for measuring flame temperature contour is proposed using the flame reaction. This method allows the temperature measurement by visualizing the flame by the luminescence of Na supplied to the form of mist. An example of temperature measurement is shown for the premixed flickering flame of methane and air. The results indicate the unsteady behavior of the temperature contour during the flickering motion.

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  • G222 スキャニングLIFと数値シミュレーションによる低フルード数浮力噴流の特異流入条件(一般講演)

    前田 篤志, 首藤 智明, 山縣 貴幸, 藤澤 延行

    熱工学コンファレンス講演論文集2010 ( 0 ) 367 - 368   2010年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

    Inflow phenomenon in near field of buoyant jet issuing into still surrounding of water is studied experimentally and numerically. The experimental visualization is carried out using 3D LIF technique, which visualizes the three-dimensional inflow phenomenon in the near field of buoyant jet. It is found from the experiment that the inflow phenomenon starts in the near field of buoyant jet when the Froude number becomes lower than the critical inflow condition. In order to understand the physics of inflow phenomenon, numerical simulation is carried out. The numerical result reproduces well the critical inflow condition observed by experiment. With further decrease in Froude and Reynolds numbers, the vigorous fluid mixing is found in the experiment, which is due to the appearance of turbulence in the jet caused by the inflow phenomenon.

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  • 1201 スキャニングLIF・PIVによる浮力噴流の3次元流れ場構造に関する研究(OS6-1 熱流体の可視化と計測1,オーガナイズドセッション:6)

    藤澤 延行, 高杉 健, 山縣 貴幸

    北陸信越支部総会・講演会 講演論文集2010 ( 0 ) 435 - 436   2010年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 1207 PIV計測に基づく角柱周りの圧力場評価における計測誤差の影響(OS6-2 熱流体の可視化と計測2,オーガナイズドセッション:6)

    山縣 貴幸, 松井 俊文, 藤澤 延行, 岡宮 正芳

    北陸信越支部総会・講演会 講演論文集2010 ( 0 ) 447 - 448   2010年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 1215 粘弾性流体の平面急縮流れにおけるPIV計測と不安定流動の発生に関する研究(OS6-3 熱流体の可視化と計測3,オーガナイズドセッション:6)

    矢島 隆宏, 穴澤 朝彦, 藤澤 延行, 山縣 貴幸

    北陸信越支部総会・講演会 講演論文集2010 ( 0 ) 463 - 464   2010年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 1221 高速噴霧液滴による液滴衝撃エロージョンに関する研究(OS6-4 熱流体の可視化と計測4,オーガナイズドセッション:6)

    工藤 靖之, 藤沢 延行, 山縣 貴幸, 松浦 史法

    北陸信越支部総会・講演会 講演論文集2010 ( 0 ) 475 - 476   2010年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

    DOI: 10.1299/jsmehs.2010.47.475

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  • 1222 2色LIF・PIVによる温度場・速度場の同時計測法の開発とノンペネトレイティブ対流への応用(OS6-4 熱流体の可視化と計測4,オーガナイズドセッション:6)

    大川 陽平, 藤澤 延行, 山縣 貴幸

    北陸信越支部総会・講演会 講演論文集2010 ( 0 ) 477 - 478   2010年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 604 噴霧ジェット装置を用いた液滴衝撃エロージョンに関する研究(一般講演-(1)《ライフサポートにおける工学技術》)

    濱 大地, 山縣 貴幸, 高野 剛, 藤澤 延行, 久我 拓海

    茨城講演会講演論文集2010 ( 0 ) 155 - 156   2010年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

    In the present paper, the erosion rate due to liquid droplet impingement has been evaluated in a small diameter range of tens of micrometers using the newly developed spray-jet apparatus. The erosion rate of aluminum material is tested with respect to the droplet parameters, such as the droplet velocity, the diameter and the number density, which are measured by optical imaging techniques. It is found that the non-dimensional erosion rate increases in proportional to the 5th power of droplet velocity, which agrees closely with that of previous study using large droplet diameters.

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  • ハイブリッド風洞による角柱後流のカルマン渦列の非定常圧力場の再現

    山縣 貴幸, 柴田 光, 早瀬 敏幸, SMIT Kasper

    日本機械学會論文集. B編 = Transactions of the Japan Society of Mechanical Engineers. B74 ( 738 ) 362 - 369   2008年2月

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    記述言語:日本語   出版者・発行元:一般社団法人日本機械学会  

    This paper deals with the hybrid wind tunnel which combines wind tunnel experiment and numerical simulation to obtain the exact and detailed information of real flows. The hybrid wind tunnel, which is based on the observer theory, utilizes partial pressure measurement of a real flow for the numerical simulation. The measured pressure is included by the simulation through a feedback loop to overcome the difficulty of specifying exact boundary or initial conditions as well as the effect of modeling error. In this paper, the reproducibility of a pressure field on the hybrid wind tunnel, which treats a fundamental flow with the Karman vortex street behind a square cylinder, is investigated by comparison with pressure measurement on the side wall of the wind tunnel. As compared with ordinary simulation, mean pressure and pressure fluctuation reproduced by the hybrid wind tunnel agree well with that of experiment with large time steps which are inappropriate for ordinary simulations. Especially, the oscillation of the pressure synchronizes with that of experiment at -4D≦x≦3D (D: cylinder width) on the side wall of the wind tunnel, showing positive correlation with the experiment. The reduction of computational cost by using large time steps enables the hybrid wind tunnel to perform real time analysis of real flows.

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  • G603 ハイブリッド風洞による角柱後流のカルマン渦列の三次元解析(2)(GS6 翼,渦,一般セッション)

    山縣 貴幸, 早瀬 敏幸

    流体工学部門講演会講演論文集2007 ( 0 ) _G603 - 1_-_G603-4_   2007年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

    This study deals with the hybrid wind tunnel which combines wind tunnel experiment and numerical simulation to obtain the exact and detailed information of real flows. The hybrid wind tunnel based on the observer theory utilizes partial information of the real flow from pressure measurement for the numerical simulation through a feedback loop to overcome the difficulty of specifying exact boundary or initial conditions as well as the effect of modeling error. In previous two-dimensional analyses on the hybrid wind tunnel, the difference between computation and experiment in regard to perturbation velocity increased with the computational grid of a high resolution due to the inappropriateness of the two-dimensional model. In this paper, three-dimensional analyses with three grid systems of different resolutions are performed on the hybrid wind tunnel for a fundamental flow with the Karman vortex street behind a square cylinder. The reproducibility of a velocity field on the hybrid wind tunnel is improved in three-dimensional analysis by using the high resolution grid system. In addition, three-dimensional analysis with the coarse grid system on the hybrid wind tunnel effectively reduces the error due to the insufficient grid resolution for ordinary numerical simulation.

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  • 310 超音波計測融合シミュレーションにおける血流の非定常流量条件の決定法(OS2-2:循環系のバイオメカニクス,オーガナイズドセッション2:循環系のバイオメカニクス)

    山縣 貴幸, 早瀬 敏幸

    バイオエンジニアリング講演会講演論文集2006 ( 0 ) 70 - 71   2007年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • G603 ハイブリッド風洞による角柱後流のカルマン渦列の三次元解析(1)(GS6 翼,渦,一般セッション)

    山縣 貴幸, 早瀬 敏幸

    流体工学部門講演会講演論文集2007 ( 0 ) _G603 - a_   2007年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 1304 ハイブリッド風洞によるカルマン渦列のリアルタイム解析の検証(2)(OS13-1 計測とシミュレーションの融合,OS13 計測とシミュレーションの融合,オーガナイズドセッション)

    山縣 貴幸, 柴田 光, SMIT Kasper, 早瀬 敏幸

    流体工学部門講演会講演論文集2006 ( 0 ) _1304 - 1_-_1304-4_   2006年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

    Numerical simulation and experiment are important tools in flow analysis, but they have advantages and disadvantages. We have proposed Measurement-Integrated simulation that integrates numerical simulation and measurement to reproduce the real flows. This new methodology reproduced the velocity field of Karman vortex street behind a square cylinder in far better agreement with the real flow than the ordinary simulation. In this paper, the pressure field obtained by the MI simulation is validated in comparison with pressure measurement on the sidewall of the wind tunnel. Results show the MI simulation successfully reproduces the pressure oscillation near the cylinder although the root-mean-square pressure is degraded in the downstream region. In addition, the pressure field of Karman vortex street is analyzed and visualized in real-time using the hybrid wind tunnel.

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  • 1304 ハイブリッド風洞によるカルマン渦列のリアルタイム解析の検証(1)(OS13-1 計測とシミュレーションの融合,OS13 計測とシミュレーションの融合,オーガナイズドセッション)

    山縣 貴幸, 柴田 光, SMIT Kasper, 早瀬 敏幸

    流体工学部門講演会講演論文集2006 ( 0 ) _1304 - a_   2006年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 906 超音波計測融合血流シミュレーションシステムにおける血流量の自動調整(OS9-2 計測とシミュレーションの融合(2),OS9 計測とシミュレーションの融合,オーガナイズドセッション)

    山縣 貴幸, 早瀬 敏幸

    流体工学部門講演会講演論文集2005 ( 0 )   2005年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

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  • 1109 超音波計測融合血流シミュレーションシステムの開発 : パラメータの自動調整(S14-2 制御と情報・生体への応用(2),S14 制御と情報・生体への応用)

    山縣 貴幸, 早瀬 敏幸

    年次大会講演論文集2005 ( 0 ) 91 - 92   2005年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

    Detailed information of the velocity and pressure field of the blood flow is essential to establish an advanced diagnosis and treatment of serious circulatory diseases. Commonly used medical measurement equipments does not provide complete information of blood flow in real-time. In this report, we develop a new blood flow measurement system applying Ultrasonic- Measurement-Integrated (UMI) simulation, that integrates ultrasonography and numerical simulation. The system consists of ultrasonic diagnostic imaging equipment, a graphics workstation, and a calculation server. Computer programs for measurement data acquisition, flow simulation, and visualization are synchronized using socket communication scheme. By considering blood flow velocity measured, the system adjusted the phase of a flow rate waveform automatically to match the cycle of pulsation in real diagnostic images.

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  • B322 傾斜遠心顕微鏡による細胞の摩擦特性の計測(B-32 生物流体(2),一般講演)

    早瀬 敏幸, 齋藤 琴美, 山縣 貴幸, 井上 浩介, 白井 敦

    日本流体力学会年会講演論文集2004   534 - 535   2004年

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    記述言語:日本語   出版者・発行元:日本流体力学会  

    In order to understand precise frictional characteristics of the red blood cells in blood capillaries, the inclined centrifuge microscope has been developed, and the frictional characteristics of blood cells on a glass plate were measured as the first step. In that research, it was the subject of discussion whether the cells glide or roll on the glass plate since the resolution of the microscope was not sufficient to distinguish the cell motion. This report deals with improvement of the observation technique for cell motion. The magnification of the inclined centrifuge microscope is increased by 5 times. The shape of red blood cells under movement can be seen clearly and cells seem to glide on the glass plate, although it is still difficult to exclude the possibility of cell rolling.

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  • 1311 数値解析による噴流構造に対するノズル長さの影響の調査

    沢村 利洋, 山縣 貴幸, 金澤 行哉

    年次大会講演論文集2002 ( 0 ) 243 - 244   2002年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

    In this study, the simulation of the cavitating jet flow which is the high speed submerged jet and spouting from nozzle is carried out, and the effects of the nozzle parallel section length on the cavitating jet is examined by the discrete vortex method the calculating results on high Reynolds number also tend to become stable easily. The result shows that the nozzle length the clear vortex structure keeps downstream exists.

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受賞

  • 優秀講演表彰

    2017年6月   日本機械学会動力エネルギーシステム部門  

    山縣 貴幸

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  • 学術奨励賞

    2008年2月   計測自動制御学会  

    山縣 貴幸

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  • 優秀発表奨励賞

    2006年11月   計測自動制御学会東北支部  

    山縣 貴幸

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共同研究・競争的資金等の研究

  • 自転公転撹拌機における内部流動と混合性能の評価に関する研究

    2018年07月 - 2019年03月

    内田エネルギー科学振興財団  試験研究費 

    山縣 貴幸

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    担当区分:研究代表者  資金種別:競争的資金

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  • 光学計測を用いた高空間解像度の流体騒音源探査システムの構築

    2013年08月 - 2014年03月

    科学技術振興機構  研究成果展開事業 研究成果最適展開支援プログラム(A-STEP)フィージビリティスタディ・ステージ 探索タイプ 

    山縣 貴幸

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    担当区分:研究代表者  資金種別:競争的資金

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  • 風車翼性能評価のための非接触圧力場計測法の開発

    2013年07月 - 2014年03月

    内田エネルギー科学振興財団  試験研究費 

    山縣 貴幸

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    担当区分:研究代表者  資金種別:競争的資金

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  • 光学計測を用いた非定常圧力場の非接触計測法の開発

    2011年12月 - 2012年07月

    科学技術振興機構  研究成果最適展開支援プログラム(A-STEP)フィージビリティスタディ・ステージ 探索タイプ 

    山縣 貴幸

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    担当区分:研究代表者  資金種別:競争的資金

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  • PIV計測を用いた3次元任意形状物体周りの圧力分布計測法の開発

    2010年07月 - 2011年03月

    内田エネルギー科学振興財団  試験研究費 

    山縣 貴幸

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    担当区分:研究代表者  資金種別:競争的資金

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  • 流体騒音評価のための非定常圧力場の可視化計測法の開発

    2009年07月 - 2010年05月

    佐々木環境技術振興財団  試験研究費 

    山縣 貴幸

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    担当区分:研究代表者  資金種別:競争的資金

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