不同SST模式在细长体绕流模拟中的应用比较

COMPARISON AMONGST DIFFERENT SHEAR-STRESS TRANSPORT MODELS IN SIMULATING THE FLOW FIELD OVER A SLENDER BODY

分别运用SST(Shear-Stress Transport)k-ω、SST-DES、SST-SAS湍流模型对亚音速条件下细长旋成体大攻角绕流流场及气动力特性进行了数值研究,通过侧向力轴向演化、物面压力分布、涡粘度变化、计算网格适应性及对流场细节的捕捉等方面比较了3种湍流模式的计算结果。数值实验表明:在相同计算条件下,3种模式对细长体后部的模拟结果差异较大,SAS模型能捕捉到更多的小尺度涡及尾涡系的非定常特性;相同横截面处涡粘度处于同一量级且大小关系为SAS<DES<SST;SAS模型模拟出的侧向力轴向演化极值更大且背涡非对称性有向尾部伸展的趋势;SAS模型与SST模型在对网格的适应性中表现较好。

The subsonic vortical flow field over a slender body at a large angle of attack was simulated using SST（Shear-Stress Transport） k-ω, SST-DES, SST-SAS turbulence models. The aerodynamic characteristics of the vortical flow were investigated. By comparing the force along the length of the slender body, surface pressure, eddy viscosity, grid suitability and the forecast of the flow field, it is concluded that under same conditions the simulation results at the rear of the slender body differ significantly amongst the three models. The SAS model is more capable in predicting the flow field, especially small-scale vortices and the unsteady characteristics of tail vortices. The eddy viscosities of the three models along the same cross-section are of the same level of magnitude, with the relation being SASDESSST. In addition, the SAS model is featured by the largest maximum force along the length of the slender body and the pattern of flow asymmetry has a trend of extending along the rear of the body. Moreover, SAS and SST models exhibit better grid suitability than the DES model.