两种湍流模式对绕椭球体三维分离流计算的比较

将新近的Shih Lumley(S L)模式应用于雷诺数为7 2×106的6∶1椭球绕流的全N S方程计算,作为参考也计算了Jonse Launder(J L)模式。在没有发生分离时,两种湍流模式计算的平均流场与实验结果符合较好。在分离发生后,J L模式计算的分离结构与实验差别很大,没有计算出二次分离线;S L模式的计算结果较好,计算得到的表面摩擦力线图谱中主要分离结构与实验结果较接近,分离区的表面压力系数分布也与实验值定性相符;在S L模式计算结果中,壁面附近出现小尺度的分离再附结构.

A Comparison of Two Turbulence Models on Computation of Three-Dimensional Separated Flow Around a Prolate Spheroid

The turbulence model Shih-Lumley (S-L) is applied to compute full N-S equations. The model Jones-Launder (J-L) is also employed for comparison. When the flow is attached, the averaged flow fields both models conform to the experiment results. But, after the separation occurs, structures of separation computed on both models deviate from the experiment results to various degrees. The difference of J-L model is bigger. The resulting low on J-L model yields no secondary separation line and thus differs appreciably from the experiment results. The main separation structures of skin friction lines computed on S-L model conform better to the experiment results, and the distribution of coefficients of wall pressure is consistent with experiment qualitatively, moreover there appears small-scale separated-reattached structures appear in the near wall region.