不同SST模型在圆柱绕流仿真中的应用比较

Application comparison of different SST models in cylindrical flow simulation

分别运用SST、SST-SAS湍流模型对Re=3 900的圆柱绕流进行了数值研究,重点从湍流结构捕捉、气动力计算等方面比较了雷诺平均RANS方法与RANS/LES混合方法的计算能力。数值结果表明:SST模型可以捕捉到流场主要特征,求解效率较高;SAS方法可以捕捉到流场小涡结构,并能较好地反映出尾迹非定常特性,但SAS求解占用更多的资源;使用SAS方法可释放更多的流场信息,求解的阻力系数、分离角等关键气动特征参数与试验值更接近;一般工程计算中推荐使用SST模型,高精度计算可使用SAS方法。

Flow past in a circular cylinder at Re=3900 is simulated using SST(Shear Stress Transport)and SST-SAS(Scale-Adaptive Simulation)methods.The model performance is assessed by a detailed comparison of predictions to the turbulence characteristics and the aerodynamic characteristics.From the assessment,it is confirmed that the SST model can solve the problem more effectively,but only capture the main flow characteristics.While,the SAS model can capture more complex flow structures and small-scale motions taking more time,which has the abilities to predict the unsteady characteristics of wake vortices advantageously.The SAS method reproduces richer physics,and therefore predicts the key aerodynamic characteristics more accurately,such as drag coefficient and separation angle.Moreover,SAS method is proposed for the high-accuracy project,while,the SST model is more reasonable in the normal solution.