Local dissipation scales and energy dissipation-rate moments in channel flow
Local dissipation scales and energy dissipation-rate moments in channel flow
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DOI：
10.1017/jfm.2012.170
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发表时间：
2012-06-25
影响因子：
3.7
通讯作者：
Schumacher, J.
中科院分区：
文献类型：
--
作者：
Hamlington, P. E.;Krasnov, D.;Schumacher, J.
利用雷诺数Re-tau = 180、381和590时的高分辨率直接数值模拟，研究了湍流通道流动的局部耗散尺度分布和能量耗散率的高阶统计量。对于足够大的Re-tau，通道体流的耗散尺度分布和能量耗散矩与均匀各向同性湍流的耗散尺度分布和能量耗散矩一致，包括最细尺度和最大尺度的弱雷诺数依赖。当y（+）小于或接近100时，当接近壁面时，分布和矩的变化是系统的，但与re -tau无关。在100 < y(+) < 200的范围内，Re-tau的最小值和两个较大值之间的矩有很大的差异。这很可能是由来自近壁区域的相干涡引起的，它们填充了低Re-tau的整个通道。
Local dissipation-scale distributions and high-order statistics of the energy dissipation rate are examined in turbulent channel flow using very high-resolution direct numerical simulations at Reynolds numbers Re-tau = 180, 381 and 590. For sufficiently large Re-tau, the dissipation-scale distributions and energy dissipation moments in the channel bulk flow agree with those in homogeneous isotropic turbulence, including only a weak Reynolds-number dependence of both the finest and largest scales. Systematic, but Re-tau-independent, variations in the distributions and moments arise as the wall is approached for y(+) less than or similar to 100. In the range 100 < y(+) < 200, there are substantial differences in the moments between the lowest and the two larger values of Re-tau. This is most likely caused by coherent vortices from the near-wall region, which fill the whole channel for low Re-tau.