湍流近壁区非线性模型的应力相位研究

The study of the phase of stresses in the nonlinear model in near wall region of turbulent flows

近年来的研究结果显示,在非平衡湍流中,线性湍流模型中的雷诺应力与平均速度变形率之间存在着相位差,但是非线性湍流模型中是否也存在这个问题,至今还没有文献涉及。针对这一问题,该文对空间周期性吹吸边界条件的槽道湍流进行了直接数值模拟。研究发现,在湍流近壁区,剪切变形的相位在典型的非线性湍流模型的主要项中起着主导作用,这使得雷诺应力与相应的模拟项之间存在相位差。因此在建立有关非线性湍流模型时也应该注意这一问题。

In recent years, studies have shown that there exists phase difference between Reynolds stress and rate of strain in linear turbulent model in non-equilibrium turbulent flows. However, whether the non-linear turbulence model also has this problem, has not yet been involved in literature. To deal with this problem, plane channel flow with spatial periodic blow and suction at one wall was studied by the means of DNS. The results show that the phase of shear stress in near wall region play the most important role in all the related terms of the typical nonlinear model. When establishing nonlinear model in non-equilibrium turbulent flows, this issue should be considered.