可压缩k-ξ湍流模式理论研究

Theoretical Analysis of Compressible k-ξTurbulence Model

基于Boussinesq涡黏性假设,选取新的第二输运变量,推导出k-ξ湍流模式的可压缩形式。针对可压缩流动的特点以及分离流动的复杂性,在可压缩k-ξ湍流模式的基础上添加应力限制器,通过限制涡黏系数的方式来达到限制湍流剪切应力以及减小湍能增幅的效果。将添加剪切应力限制器的k-ξ可压缩湍流模式用于RAE2822翼型流场数值模拟,结果表明:压力系数及不同截面速度与实验值符合较好,且在分离与掺混的复杂流动区域,修正后的k-ξ湍流模式数值模拟结果优于k-ε模式及k-ω模式。

Based on the Boussinesq eddy viscosity hypothesis,compressible k-ξmodel had been derived from the typical two-equation turbulence models,with a new second transport variable.Due to the characteristics of compressible flow and the complexity of separated flow,a shear stress correction term was added to the compressible k-ξmodel.It was as a supplement to avoid oversize turbulent kinetic energy.The flow field over RAE2822 was numerically simulated by new model with the shear stress limiter on OpenFOAM.It was indicated that the results with new model were better than those with k-εmodel and k-ωmodel in complex flow areas with separation and mixing.The pressure coefficient and the velocity type at different sections were good agreement with experimental values.