Self-sustaining processes at all scales in wall-bounded turbulent shear flows.
Self-sustaining processes at all scales in wall-bounded turbulent shear flows.
复制标题
壁面湍流剪切流中所有尺度的自持过程。
DOI：
10.1098/rsta.2016.0088
复制
发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Cossu C
中科院分区：
文献类型：
--
作者：
Cossu C
我们收集和讨论了我们最近的研究结果，这些研究表明在壁面边界湍流剪切流中存在一整套自持运动的证据，其尺度从缓冲层条纹到外层的大尺度和超大尺度运动。这类与条纹和准流向涡相联系的自持运动的统计和动力学特征与汤森附加涡旋的特征是一致的。每个相关尺度的运动都能够在没有来自大尺度或小尺度运动的强迫的情况下，通过相干的抬升效应从平均流中提取能量来维持自身。相干自持过程被嵌入到滤波的N-S方程的一组不变解中，该不变解充分考虑了与剩余小尺度运动相关的雷诺应力。本文是“发展大雷诺数下高保真的壁面湍流模型”主题的一部分。
We collect and discuss the results of our recent studies which show evidence of the existence of a whole family of self-sustaining motions in wall-bounded turbulent shear flows with scales ranging from those of buffer-layer streaks to those of large-scale and very-large-scale motions in the outer layer. The statistical and dynamical features of this family of self-sustaining motions, which are associated with streaks and quasi-streamwise vortices, are consistent with those of Townsend’s attached eddies. Motions at each relevant scale are able to sustain themselves in the absence of forcing from larger- or smaller-scale motions by extracting energy from the mean flow via a coherent lift-up effect. The coherent self-sustaining process is embedded in a set of invariant solutions of the filtered Navier–Stokes equations which take into full account the Reynolds stresses associated with the residual smaller-scale motions.This article is part of the themed issue ‘Toward the development of high-fidelity models of wall turbulence at large Reynolds number’.