Details of a Researcher - Obi, Shinnosuke

Papers - Obi, Shinnosuke

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第 11 回生研 NST シンポジウム講演論文集第 11 回生研 NST シンポジウム講演論文集 9, 1996

姫木仲秋，小尾晋之介，益田重明，吉岡修哉，枡川高久，小尾晋之助

日本機械学会論文集. B 編 65 (00629), 179-184 1999

代数応力モデルによる二次元非対称ディフューザ内乱流はく離の数値予測

沖永佳史，小尾晋之介

年会一般講演 18, 421-422 1999

マイクロバーストの実験室モデル (平板に衝突する渦輪の速度場)

長田泰一，益田重明，小尾晋之介

大会講演予講集 76, 403 1999

乱流モデル応用研究会の活動について

藤原仁志，小尾晋之介，山本誠，半場藤弘，岡本正芳，秋山実，荒木和博， ...

航空宇宙技術研究所特別資料 44, 281-284 1999

Turbulent statistics of Backward-Facing step flow with periodic perturbations

Yoshioka S., Masukawa T., Obi S., Masuda S.

Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B (Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B) 65 ( 629 ) 179 - 184 1999

ISSN 03875016

The experimental study has been conducted on the influence of the periodic perturbation on the separated flow over a backward-facing step. In order to investigate the large-scale eddy motion, which is evolved from the step edge due to the periodic suction and injection, the Particle Image Velocimeter has been introduced. The effect of the perturbation is obvious in reduction of the reattachment length, providing at most the reduction by over 30% against that of the steady flow condition. The investigation on the turbulent transport term in the mean momentum equation reveals the increase in the individual components of Reynolds stress is responsible for the activated momentum transfer across the shear layer, which in turn results in the earlier flow reattachment. The general tendency is in good accordance with other studies in past, though the relative level of the turbulent shear stress is somewhat low. Further investigation on this point is necessary.

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Role of the vortex motion in the periodically perturbed turbulent separated flow over the backward-facing step

Yoshioka, S. Obi, S. and Masuda, S.

4th KSME-JSME Fluids Engineering Conference 585-588 1998.10

Research paper (conference, symposium, etc.), Joint Work, Accepted

周期的外乱を受けるバックステップ流の運動量輸送について

吉岡修哉，小尾晋之介，益田重明

年会一般講演 17, 223-224 1998

単一傾斜型熱線風速計による二次元混合層の乱流計測

小形俊夫，前鶴昭徳，小尾晋之介，益田重明

年会一般講演 17, 183-184 1998

二次元非対称ディフューザ内乱流のはく離予測について

冲永佳史，小尾晋之介

年会一般講演 17, 179-180 1998

2・2 境界層 (2. 非圧縮性流れ)(流体工学機械工学年鑑 (1997 年))

小尾晋之介

日本機械学會論文集. B 編 64 (624), 2368 1998

チャネル乱流の壁面せん断応力統計量に関する実験的研究

小尾晋之介

日本流体力学会誌「ながれ」 17 (2), 74-79 1998

The mechanism of momemtum transfer enhancement in the periodically perturbed turbulent separated flow

Obi, S. Ishibashi, N. Masuda, S.

2nd Int. Symp. Turbulence, Heat and Mass Transfer 835-844 1997.06

Research paper (conference, symposium, etc.), Joint Work

周期的外乱によるディフューザ内乱流はく離流の制御 (制御効果と速度場の変化)

石橋信正、青木謙太、小尾晋之介、益田重明

日本機械学会論文集B編 63巻 ( 605号 ) 1997.01

Research paper (conference, symposium, etc.), Joint Work

Control of turbulent separated flow in a plane diffuser using periodic perturbation (control effects and response of velocity field)

Ishibashi N., Aoki K., Obi S., Masuda S.

Nippon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B (Nippon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B) 63 ( 605 ) 62 - 68 1997.01

ISSN 03875016

The effects of periodic perturbation on turbulent separated flow in a two-dimensional asymmetric diffuser were investigated. Measurements of velocity fields were undertaken using a LDV, and data reduction was conducted on a time-averaged as well as ensemble-averaged manner that made the mean-periodic-turbulent decomposition possible. Effects of imposed perturbation on the velocity field strongly depend on the frequency of the perturbation, and the optimum frequency ranges between 0.01≤St≤0.04, with St being the perturbation frequency normalized by the channel height at the diffuser inlet and the maximum inlet velocity. At the optimum frequency, the effect of perturbation appears as an organized velocity fluctuation along a separated shear flow, resulting in the enhancement of momentum transport, which is the primary effect of imposed perturbation. An increase in the turbulent Reynolds stress component in the recirculation region is also observed, indicating the secondary effect of the organized fluid motion due to periodic perturbation.

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周期的外乱に対するバックステップ流の応答特性

枡川高久，吉岡修哉，斎藤武，小尾晋之介，益田重明

年会一般講演 16, 281-282 1997

周期的外乱によるディフユーザ内乱流はく離流の制御

石橋信正，青木謙太，小尾晋之介，益田重明

日本機械学会論文集 B 編 63 (605), 62-68 1997

二次元混合層における乱流エネルギー収支の測定

小形俊夫，伊藤健二，小尾晋之介，益田重明

年会一般講演 16, 107-108 1997

周期的外乱によるディフユーザ内乱流はく離流の制御制御効果と速度場の変化

石橋信正，青木謙太，小尾晋之介，益田重明

日本機械学会論文集 B 編 63 (605), 62-68 1997

レイノルズ応力の乱流輸送モデル (速度変動三次モーメントの輸送方程式による検討)

原英統、小尾晋之介

日本機械学会論文集B編 62巻 ( 600号 ) 1996.08

Research paper (conference, symposium, etc.), Joint Work

Model of the turbulent transport of Reynolds stress (Study on the transport equation of triple velocity moment)

Hara H., Obi S.

ISSN 03875016

An algebraic model of the turbulent transport of Reynolds stress is proposed, based on an examination of the budget of the transport equation for the third-moment of fluctuating velocity. Combined with a basic version of the second-moment closure, the new model is applied to the calculation of a two-dimensional free mixing layer. The results show a slight modification of the conventional gradient transport model for the turbulent diffusion, and yield a better agreement with experimental results in terms of the amplitude of the third-moment. The inclusion of a simple model for the pressure diffusion term indicates the possibility of further improvement of the turbulent transfer process in free flows.

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