Direct test of a nonlinear constitutive equation for simple turbulent shear flows using DNS data
Direct test of a nonlinear constitutive equation for simple turbulent shear flows using DNS data
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DOI：
10.1016/j.cnsns.2006.01.015
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发表时间：
2007-10
影响因子：
3.9
通讯作者：
F. Schmitt
中科院分区：
文献类型：
--
作者：
F. Schmitt
人们提出了几个非线性本构方程来克服线性涡粘模型描述复杂湍流的局限性。这些非线性方程经常通过数值模型的输出与实验数据进行比较。在这里，我们使用简单剪切流的直接数值模拟 (DNS) 对非线性涡粘模型进行先验分析。在本文中，使用涉及多个流动不变量的张量投影直接检查本构方程。这提供了 3 项展开，对于 2D 流来说是精确的，并且是 3D 流的最佳近似。我们利用 DNS 数据给出了简单剪切流近壁区域的二次非线性本构方程，并估计了它们的系数。我们表明，对于所考虑的不同简单剪切流数据库，这些系数具有几个共同的属性。我们还表明，在管流的中心区域，剪切率非常小，本构方程的系数发散，表明这种消失剪切的表示法失败。
Several nonlinear constitutive equations have been proposed to overcome the limitations of the linear eddy-viscosity models to describe complex turbulent flows. These nonlinear equations have often been compared to experimental data through the outputs of numerical models. Here we perform a priori analysis of nonlinear eddy-viscosity models using direct numerical simulation (DNS) of simple shear flows. In this paper, the constitutive equation is directly checked using a tensor projection which involves several invariants of the flow. This provides a 3 terms development which is exact for 2D flows, and a best approximation for 3D flows. We provide the quadratic nonlinear constitutive equation for the near-wall region of simple shear flows using DNS data, and estimate their coefficients. We show that these coefficients have several common properties for the different simple shear flow databases considered. We also show that in the central region of pipe flows, where the shear rate is very small, the coefficients of the constitutive equation diverge, indicating the failure of this representation for vanishing shears.