基于尺度相似假设的大涡模拟动力方法

Dynamic procedure based on the scale-similarity hypotheses for large-eddy simulations

当前的大涡模拟动力方法对G erm ano等式中的两个尺度的亚格子应力均使用相同的亚格子基模型。这样为求得基模型系数,必须假定该系数在测试滤波操作下保持不变。但实际上该系数存在剧烈的脉动,与假定并不一致。该文提出的方法对以上两个应力分别应用亚格子基模型和尺度相似假设。这样就无需对系数分布做出假定并保证了方法的内在一致性。用该方法对R e为104的方腔流动进行了大涡模拟。结果表明该方法对流动统计量的预测有所改进,并可有效消除亚格子模型系数的奇异性。

Current large-eddy simulations treat the two subgrid-scale stresses in the Germano identity with the same subgrid base model. Thus to get the base model coefficient, the coefficient must be assumed to be constant for test filter operation. However, since the coefficient has sharp fluctuations, this assumption is inconsistent. A new dynamic procedure was developed in which these two stresses are modeled by the base model and the scale-similarity hypotheses. Large-eddy simulations of lid-driven cavity flow at a Reynolds number of 104 show that the procedure improves both the flow statistics and removes the singularity of the Smagorinsky model coefficient.