高解像度DNSデータベースを用いた高レイノルズ数チャンネル乱流場の四象限・確率密度関数解析

抄録

Direct Numerical Simulations (DNS) resolved Kolmogolov scales were employed to investigate large-scale structure in fully developed turbulent channel flows. Quadrant and probability density function analyses were conducted over a decoupled range of Reynolds numbers (Re_τ), 150, 400, 1000, and 2000, based on the friction velocity and channel half-width. The quadrant analysis has proved a larger contribution of sweep event to the Reynolds shear stress with increasing Reynolds number at each location from the wall to the channel center. This suggests that energy transfer increased on large-scale structure from outer region to inner region. In contrast, at each location from the wall, the PDF profiles of turbulent velocities and pressure have the analogous them uninfluenced by increasing Reynolds number. In near log-law region, Kullaback-Leibler divergence profiles of the streamwise turbulent velocity have the V-shaped them in cases of Re_τ> 400.