Large-eddy simulation of the turbulent mixing layer
Large-eddy simulation of the turbulent mixing layer
复制标题
DOI：
10.1017/s0022112097005429
复制
发表时间：
1997-05
影响因子：
3.7
通讯作者：
Bert Vreman;B. Geurts;H. Kuerten
中科院分区：
文献类型：
--
作者：
Bert Vreman;B. Geurts;H. Kuerten
通过对弱可压缩时间混合层的大涡模拟，对湍流应力张量的六种亚格子模式进行了检验：Smagorinsky模式、相似模式、梯度模式、动力涡粘性模式、动力混合模式和动力Clark模式。后三个模型是使用动态方法的前三个模型的变体。为了评估这六个模型的质量，进行了两组模拟。将对应于第一集合的LES结果与从直接数值模拟(DNS)获得的过滤结果进行比较。动态模型的结果似乎比测试的非动态模型更准确。一个足够的机制来将能量从分解到次网格尺度上的消散是至关重要的。动力学模型具有这一性质，但Smagorinsky模型在相变过程中耗散太大，而相似和梯度模型对于最小分辨尺度而言耗散不足。在这组模拟中，在中等雷诺数时，动态混合模型和Clark模型被发现比动态涡粘性模型稍微精确一些。第二套大涡模拟涉及雷诺数较大、计算范围较大的混合层。目前还不能对该混合层进行准确的数值模拟，因此，在这种情况下，通过研究大涡模拟是否与自相似湍流相似来测试大涡模拟。结果表明，动态模型比非动态模型产生了更好的结果。利用动态涡粘模型得到了与自相似状态最接近的近似解。
Six subgrid models for the turbulent stress tensor are tested by conducting large-eddy simulations (LES) of the weakly compressible temporal mixing layer: the Smagorinsky, similarity, gradient, dynamic eddy-viscosity, dynamic mixed and dynamic Clark models. The last three models are variations of the first three models using the dynamic approach. Two sets of simulations are performed in order to assess the quality of the six models. The LES results corresponding to the first set are compared with filtered results obtained from a direct numerical simulation (DNS). It appears that the dynamic models lead to more accurate results than the non-dynamic models tested. An adequate mechanism to dissipate energy from resolved to subgrid scales is essential. The dynamic models have this property, but the Smagorinsky model is too dissipative during transition, whereas the similarity and gradient models are not sufficiently dissipative for the smallest resolved scales. In this set of simulations, at moderate Reynolds number, the dynamic mixed and Clark models are found to be slightly more accurate than the dynamic eddy-viscosity model. The second set of LES concerns the mixing layer at a considerably higher Reynolds number and in a larger computational domain. An accurate DNS for this mixing layer can currently not be performed, thus in this case the LES are tested by investigating whether they resemble a self-similar turbulent flow. It is found that the dynamic models generate better results than the non-dynamic models. The closest approximation to a self-similar state was obtained using the dynamic eddy-viscosity model.