采用RANS/LES混合方法研究分离流动

Simulation of separation flows with RANS/LES hybrid methods

采用结合湍流模式和大涡模拟(LES)的混合方法数值模拟Aerospatial A-profile翼型以及细长椭球体大迎角分离流动。该类混合方法比较适于模拟分离流动:近壁区附体流动采用湍流模式,而远离物面分离区域内的大尺度运动则用LES方法。通过计算和实验结果的对比,混合方法切实可行并具有很大的发展潜力。

RANS/LES hybrid methods based on some typical turbulence models such as Baldwin-Lomax （B-L） model, Sparlart-Allmaras （S-A） model and LFS-type Smagorinsky sub-grid stress model, are presented here to simulate the separated flows around an airfoil named as Aerospatial A-profile and a 6：1 ellipsoid at high angle of attack. Higher order central with artificial viscosity and fully implicit LU-SGS-τTS methods are applied to solving the Navier-Stokes equations. The hybrid methods are very suitable for the separated flows with the turbulence model behavior near the solid wall and LES behav- ior in the large scale unsteady 3-dimensional core flow regions. From the comparison of results between computation and experiment, the hybrid methods are practicable and hopeful.