Sajben跨声速扩压器分离流动中湍流模式数值研究

Numerical Study of Turbulence Models in Sajben Diffuser Transonic Separation Flow

为研究湍流模式对激波/湍流边界层干扰内流流动的影响,提高数值计算准确度,使用SA,SST k-ω,非线性EASM k-ω,Gao-Yong四个湍流模式对Sajben扩压器内激波/湍流边界层干扰流动进行了数值计算。对流项采用Roe格式离散,扩散项采用二阶中心格式离散,离散后的控制方程用多步Runge-Kutta显示时间推进法求解。文中展示了四个湍流模式计算得到的壁面压力、速度剖面、摩阻系数等分布。计算值与实验值符合很好,四个湍流模式总体上能够较好地模拟扩压器内激波/湍流边界层干扰复杂分离流动。Gao-Yong湍流模式对分离区内的压力、速度型的模拟更加准确,而非线性EASM k-ω模式对分离再附点位置计算最理想。

In order to study the effects of turbulence mode on the shockwave turbulent boundary layer interaction in internal flow and improve the accuracy of numerical simulation,numerical simulation of shockwave turbulence boundary layer interaction in Sajben diffuser flowfield is implemented based on S-A,SST k-ω,nonlinear EASM k-ω and Gao-Yong turbulence models. Convection terms and diffusion terms are calculated using Roe scheme and tow order center difference scheme,respectively. The Multi-step Runge-Kutta explicit time marching method is employed to solve space discrete control equations. Pressure distribution on the wall surface,velocity profile distribution and skin friction distribution obtained by four turbulence models are presented. The numerical results agree well with the experimental data. In general,four turbulence models work well in numerical simulation of Sajben diffuser complex separation flow. Gao-Yong turbulence model has a powerful capability to simulate pressure and velocity profile distribution,especially in separated region. Nonlinear EASM k-ω turbulence model can predict location of separation and reattachment better than others.