Faculty Profiles - Suzuki Hiroki

S0502-7-4 On statistical properties of turbulent boundary layers affected by free-stream turbulence

TSUKUDA Saori, SUZUKI Hiroki, KITAYAMA Tomoyuki, NAGATA Kouji, SAKAI Yasuhiko

The proceedings of the JSME annual meeting 2010 217 - 218 2010

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

The effects of free-steam turbulence on a turbulent boundary layer are experimentally investigated by using a wind tunnel. For the case with free stream turbulence, turbulence-generating grid is placed upstream of the leading end of a flat plate, on which turbulent boundary layer is developed. The Reynolds number based on the momentum thickness is Re_θ=2990 for the case with and without grid turbulence. Instantaneous streamwise velocity is measured using a hot-wire anemometry with an inhouse I-type probe. The effects of free-stream turbulence on statistical properties of the turbulent boundary layer are discussed.

DOI： 10.1299/jsmemecjo.2010.2.0_217

S0502-7-3 Experimental Analysis of High-Schmidt-Number Scalar Mixing by means of High-Accuracy PLIF Technique

UKAI Ryota, SUZUKI Hiroki, NAGATA Kouji, SAKAI Yasuhiko

The proceedings of the JSME annual meeting 2010 215 - 216 2010

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

High-Schmidt-number scalar mixing layers in the grid turbulence are experimentally investigated in a water channel by means of the planar laser induced fluorescence (PLIF) technique and the time-resolved particle image velocimetry (PIV). A biplane square grid and a fractal square grid are used to generate turbulence. The Reynolds number based on the effective mesh size and mean velocity is 2,500 in both flows. Fluorescent dye (Rhodamine B; Schmidt number is about 2,100) is homogeneously premixed only in the upper stream, and therefore, the scalar mixing layer with an initial step profile develops downstream of the grid. Various turbulence quantities are evaluated and comparisons are made between turbulence and scalar fields generated by the regular and fractal grids.

DOI： 10.1299/jsmemecjo.2010.2.0_215

Direct numerical simulation of fractal-grid generated turbulence using an immersed boundary method and high accuracy finite-difference schemes Reviewed

Direct numerical simulation of turbulent mixing in regular and fractal grid turbulence Reviewed

Hiroki Suzuki, Kouji Nagata, Yasuhiko Sakai, Toshiyuki Hayase

Physica Scripta T T142 2010

Turbulence structure of multiscale generated turbulence by fractal grids and scalar transfer mechanism (2nd report, DNS on the influence of grid parameters on homogeneity, isotropy and intermittency) Reviewed

Hiroki Suzuki, Kouji Nagata, Yasuhiko Sakai, Toshiyuki Hayase

Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B 76 ( 772 ) 2024 - 2031 2010

The image correction method for PLIF measurements of high-schmidt-number scalar transfer (Nonmetric corrections for temporospatial variation of laser intensity and time variation of fluorescence quantum yield) Reviewed

Hiroki Suzuki, Kouji Nagata, Yasuhiko Sakai, Ryota Ukai

Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B 76 ( 770 ) 1543 - 1551 2010

Hiroki Suzuki, Kouji Nagata, Yasuhiko Sakai, Toshiyuki Hayase

Transaction of the Japan Society for Mathematical Science (in Japanese) 11 ( 1 ) 33 - 38 2009.12

Turbulence Structure of Multiscale Generated Turbulence by Fractal Grids and Scalar Transfer Mechanism : 1st Report, DNS on the Effect of Fractal Shapes on Turbulent Flow Field Reviewed

Hiroki Suzuki, Kouji Nagata, Yasuhiko Sakai, Toshiyuki Hayase, Takashi Kubo

Transactions of the Japan Society of Mechanical Engineering Series B (in Japanese) 75 ( 755 ) 1387 - 1394 2009.7

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：The Japan Society of Mechanical Engineers

Turbulence characteristics in the spatially developing fractal-generated turbulence are investigated by means of the direct numerical simulation (DNS). Three kinds of fractal grids, namely, cross, I and square types, are numerically constructed using the immersed boundary method. The results show that fractal grids generate high turbulence intensities compared with the classical grid turbulence using a biplane square mesh grid at the same mesh Reynolds number. Among the three types, the fractal square grid is the best to generate nearly homogeneous and isotropic turbulence in the far downstream decaying region. The integral length scale in the fractal generated turbulence remains approximately constant in the decaying region, whereas it grows downstream in the classical grid turbulence. These results are in good agreement with the previous experiments.

DOI： 10.1299/kikaib.75.755_1387