研究者詳細 - 鈴木　博貴

論文 - 鈴木　博貴

分割表示 162 件中 121 - 140 件目／全件表示 >>

Direct Numerical Simulation of Single-Square Grid-Generated Turbulence 査読

Y. Zhou, K. Nagata, Y. Sakai, H. Suzuki, Y. Ito, O. Terashima, T. Hayase

(全文査読付) Proceedings of the 4th International Conference on Jets, Wakes and Separated Flows paper No. 1102 - (5 pages) 2013年9月

Effects of Initial Condition on Coherent Structure and Evolution of Turbulent Plane Jets 査読

N. Wu, Y. Sakai, K. Nagata, H. Suzuki, O. Terashima, T. Hayase

(全文査読付) Proceedings of the 4th International Conference on Jets, Wakes and Separated Flows paper No. 1010 - (6 pages) 2013年9月

Measurement of Axial Turbulent Scalar Flux of High Sc/Low Re Round Jet Using Line Scan Camera 査読

Hiroshi Nishiyama, Tatsuo Ushijima, Hiroki Suzuki, Yutaka Hasegawa

(全文査読付) Proceedings of the 4th International Conference on Jets, Wakes and Separated Flows Paper No. 1193 - (5 pages) 2013年9月

Development and Quantitative Validation of a Numerical Code Using Highly Energy-Conservative Scheme 査読

Masaya Watanabe, Hiroki Suzuki, Yutaka Hasegawa, Tatsuo Ushijima

(全文査読付) Proceedings of the 4th International Conference on Jets, Wakes and Separated Flows Paper No. 1170 - (4 pages) 2013年9月

DNS Study on Pressure Characteristics of Fractal- Generated Turbulence 査読

Hiroki Suzuki, Kouji Nagata, Yasuhiko Sakai, Toshiyuki Hayase, Yutaka Hasegawa, Tatsuo Ushijima

(全文査読付) Proceedings of the 4th International Conference on Jets, Wakes and Separated Flows Paper No. 1109 - (4 pages) 2013年9月

DNS on Multiscale- Generated Grid Turbulence Using Classical Grid 査読

Hiroki Suzuki, Kouji Nagata, Yasuhiko Sakai, Toshiyuki Hayase, Yutaka Hasegawa, Tatsuo Ushijima

(全文査読付) Proceedings of the 8th International Symposium on Turbulence and Shear Flow Phenomena Paper No. HOM1E - (6 pages) 2013年8月

Analysis of Flow Characteristics of Turbulent Plane Jets Based on Velocity and Scalar Fields Using DNS 査読

Nannan Wu, Yasuhiko Sakai, Kouji Nagata, Hiroki Suzuki, Osamu Terashima, Toshiyuki Hayase

Journal of Fluid Science and Technology 8 ( 3 ) 247 - 261 2013年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：The Japan Society of Mechanical Engineers

Turbulent plane jets are prototypical free shear flows on which fundamental research can expand the overall understanding of turbulent flows. In this study, flow characteristics of the turbulent plane jets are studied by means of direct numerical simulation (DNS) based on the finite difference method. The effects of the initial conditions at the jet exit (i.e. Reynolds number and velocity profile) on the spatial development of velocity and scalar fields are mainly investigated. Meanwhile the instantaneous coherent structures, based on the Q-criterion and the local minimum of pressure, are presented. The results suggest that the plane jet flow with the higher Re (=U_bd/ν : U_b is the bulk mean velocity at the jet exit, d is the slot width, and ν is the kinematic viscosity) and the parabola velocity profile at the jet exit will correspond to the shorter potential core, furthermore, the lower Re and the parabola velocity profile will strengthen the decay of the mean field in the process of flow transition to full turbulence. The flow self-similarity will be achieved at shorter streamwise distance from the jet exit for the higher Re and the parabola velocity profile at the jet exit. Moreover, the dependency of coherent structures on the initial Reynolds number is remarkable, especially in the flow development region, but the change of initial velocity profile at the jet exit hardly acts on the scale of coherent structures. It is also observed that the scalar field is more sensitive to changes of initial conditions than the velocity field.

DOI： 10.1299/jfst.8.247

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Fractal analysis of turbulent mixing in fractal-generated turbulence by planar laser-induced fluorescence 査読

Hiroki Suzuki, Kouji Nagata, Yasuhiko Sakai, Yutaka Hasegawa

Physica Scripta 88 ( 155 ) 014062 - (5 pages) 2013年7月

An Attempt to Improve Accuracy of PIV Using an Interpolation Method 査読

Hiroki Suzuki, Tatsuo Ushijima, Yutaka Hasegawa, Kouji Nagata, Yasuhiko Sakai

(全文査読付) Proceedings of the 12th Asian Symposium on Visualization Paper No.218 - (4 pages) 2013年5月

Visualization of turbulent reactive jet by using direct numerical simulation 査読

Tomoaki Watanabe, Yasuhiko Sakai, Kouji Nagata, Osamu Terashima, Hiroki Suzuki, Toshiyuki Hayase, Yasumasa Ito

International Journal of Modeling, Simulation, and Scientific Computing 4 ( SUPPL.1 ) 1341001 - (16 pages) 2013年

フラクタル格子乱流の空間発展に関する風洞実験（第2報，I型及びX型熱線プローブを用いた乱流場の乱れエネルギ輸送の計測）査読

稲葉拓人, 長田孝二, 酒井康彦, 鈴木浩之, 寺島修, 鈴木博貴

日本機械学会論文集 B編 79 ( 804 ) 1476 - 1488 2013年

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：一般社団法人日本機械学会

Spatial development of a turbulent field generated by a multiscale, fractal-grid is investigated in a wind tunnel. A square type (i.e., fractal elements with square shapes) fractal grid is placed at the inlet of the test section. The Reynolds number based on the length of the biggest grid bar is set to 5900. The spatial developments of cross-sectional profiles of turbulent kinetic energy K, dissipation rate of K, ε, and the advection, production, triple-correlation transport, pressure transport and viscous diffusion terms in the transport equation of K are measured by using a hot wire anemometer. The results show that in the upstream region, turbulence produced by the biggest grid bar is transported to the central and outward regions by the triple-correlation term T. In the decay region, there is low turbulence production downstream of the interior of the biggest grid bar, which is mainly transported outward rather than to the central region by T. The advection term is large and positive in the decay region whereas the pressure transport and the viscous diffusion terms are very small in the decay region.

DOI： 10.1299/kikaib.79.1476

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フラクタル格子乱流の空間発展に関する風洞実験（第1報，I型熱線プローブを用いた乱流場の基本特性の計測）査読

鈴木浩之, 長田孝二, 酒井康彦, 鈴木博貴, 寺島修, 稲葉拓人

日本機械学会論文集 B編 79 ( 798 ) 115 - 125 2013年

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：一般社団法人日本機械学会

Spatial development of a turbulent field generated by a multiscale, fractal-grid is investigated in a wind tunnel. A square type (i.e., fractal elements with square shapes) fractal grid is placed at the inlet of the test section. The Reynolds numbers based on the length of the biggest grid bar are set to 5900 and 11400. Turbulent characteristics in the downstream region of the grid are measured by using a hot wire anemometer. The results on the centerline statistics are compared with those in the previous experiments at the same Reynolds numbers. The results on the centerline statistics generally agree with the previous measurements despite the difference in the size of the test sections used. The spatial developments of cross-sectional profiles are also measured. It is found that the non-uniformity in the mean velocity field almost disappear in the downstream direction, although the non-uniformities of higher-order statistics are still observed even in the far downstream region. In the entire cross section of the tunnel, the ratio of the integral length scale L_u to the Taylor microscale λ hardly changes in the decay region of the rms velocity. These results will provide useful information in clarifying the non Richardson-Kolmogorov cascade process in the fractal-generated turbulence found in the previous measurement (Mazellier and Vassilicos, Physics of Fluids, Vol. 22, 075101 2010).

DOI： 10.1299/kikaib.79.115

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Turbulence structure and turbulence kinetic energy transport in multiscale/fractal-generated turbulence 査読

Kouji Nagata, Yasuhiko Sakai, Takuto Inaba, Hiroki Suzuki, Osamu Terashima, Hiroyuki Suzuki

Physics of Fluids 25 ( 6 ) 065102 - (26 pages) 2013年

正方格子およびフラクタル格子乱流場における高シュミット数スカラ混合に関する実験的研究査読

星野晃一, 長田孝二, 酒井康彦, 鈴木博貴, 鵜飼涼太, 寺島修, 伊藤靖仁

日本機械学会論文集 B編 79 ( 799 ) 304 - 316 2013年

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：一般社団法人日本機械学会

High-Schmidt-number scalar mixing layers in a turbulent flow generated by regular and fractal grids are investigated by means of experiments using particle image velocimetry (PIV) and planar laser induced fluorescence (PLIF) technique. The Reynolds number based on the mesh size is 2,500. Rhodamine B is used as a fluorescent dye. The Schmidt number is about 2,100. The flow is separated into upper and lower layers by a splitter plate installed upstream of the grids; thus, the turbulent scalar mixing layers develop downstream of the grids. The results show that fractal grid turbulence has stronger turbulence intensity than that in regular grid turbulence. The decay exponent of turbulence intensity, n, is n = 1.21 for the regular grid and n = 1.40 for the fractal grid. The eddy diffusivity for mass in fractal grid turbulence is approximately four times larger than that in regular grid turbulence. The scalar dissipation in fractal grid turbulence is smaller than that in regular grid turbulence. Finally, it is concluded that turbulent scalar mixing is more enhanced by the fractal grid than by the regular grid.

DOI： 10.1299/kikaib.79.304

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乱流境界層の統計的特性に及ぼす円柱後流による主流乱れの影響査読

晝田紘佑, 長田孝二, 酒井康彦, 鈴木博貴, 寺島修

日本機械学会論文集 B編 79 ( 799 ) 291 - 303 2013年

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：一般社団法人日本機械学会

Effects of the cylinder wake in a freestream on statistical properties of a turbulent boundary layer over a flat plate are investigated by means of wind tunnel experiments. The cylinder is set horizontally over the flat plate and the interactions between its wake and the zero-pressure-gradient turbulent boundary layer are investigated. Instantaneous velocity is measured by using hot wire anemometry. The bursting events are detected by the variable interval time average (VITA) technique. The results show that the time-averaged mean velocity in the inner layer with the cylinder wake coincides with that without the cylinder wake. However, turbulence intensities normalized by the inner parameters are suppressed by the cylinder wake. It is found that the peak value of the velocity fluctuation during the sweep phase in the bursting event is increased by the cylinder wake.

DOI： 10.1299/kikaib.79.291

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Quantitative visualization of high-Schmidt-number turbulent mixing in grid turbulence by means of PLIF 査読

Hiroki Suzuki, Kouji Nagata, Yasuhiko Sakai

Journal of Visualization 15 ( 2 ) 109 - 117 2012年5月

Investigation of Eddy Diffusivity in a Reactive Plane Jet by using Direct Numerical Simulation 査読

Tomoaki Watanabe, Yasuhiko Sakai, Kouji Nagata, Osamu Terashima, Yasumasa Ito, Hiroki Suzuki, Toshiyuki Hayase

(全文査読付) Communications in Computer and Information Science 323 CCIS ( PART 1 ) 144 - 150 2012年

輝度分布補間によるPIV計測精度向上（擬似粒子画像によるフーリエ補間の導入効果の解析）査読

鈴木博貴, 長田孝二, 酒井康彦, 長谷川豊

日本機械学会論文集（B編） 78 ( 790 ) 1248 - 1259 2012年

Quantitative Visualization of High-Schmidt-Number Scalar Mixing in Grid Turbulence 査読

Hiroki Suzuki, Kouji Nagata, Yasuhiko Sakai

(全文査読付) Proceedings of the 11th Asian Symposium on Visualization Paper No. ASV11-04-05 - (8 pages) 2011年6月

An experimental study on turbulent mixing of high-Schmidt-number scalar in grid turbulence by means of PIV and PLIF 査読

Hiroki Suzuki, Kouji Nagata, Yasuhiko Sakai, Ryota Ukai

ASME-JSME-KSME 2011 Joint Fluids Engineering Conference, AJK 2011 1 ( D ) 3763 - 3767 2011年

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