Statistical properties of a coherent structure function FCS are investigated using DNS data for homogeneous isotropic turbulence and turbulent channel flows. The function FCS is defined as the second invariant Q of a velocity gradient tensor normalized by the magnitude E of the velocity gradient tensor. In homogeneous isotropic turbulence, the probability density function (pdf) of FCS shows good agreement at different Reynolds number. The volume fraction of positive Q and the average of FCS converge to a certain value at high Reynolds number. For the turbulent channel flows, the pdf of FCS at different Reynolds number coincides very well at the distance from the wall in wall units. The profiles of the conditional average of positive and negative Q, the volume fraction, and the near-wall FCS 2 are in good agreement at different Reynolds number and those profiles are given as a function of the distance from the wall in wall units.
|出版ステータス||Published - 2009|
|イベント||6th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2009 - Seoul, Korea, Republic of|
継続期間: 2009 6月 22 → 2009 6月 24
|Other||6th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2009|
|国/地域||Korea, Republic of|
|Period||09/6/22 → 09/6/24|
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