使用GAO-YONG湍流方程组对扩压器流动的计算

采用基于同位网格的SIMPLE方法求解GAO-YONG不可压湍流方程组,对二维扩压器流动进行了数值模拟.通过界面速度动量插值法解决了压力锯齿波问题,并且采用了正交贴体网格和二阶QUICK格式离散对流项以提高计算精度.与实验结果以及BL(Baldw-Lomax)模型计算结果的比较表明,不需要任何经验系数及壁面函数的GAO-YONG不可压湍流模型方程组能够对有压力梯度的湍流流动做出很好的预测.计算发现,在机械能方程中引入平均流压力梯度的作用,对GAO-YONG湍流方程组正确模拟逆压力梯度流动起到了关键作用.

Calculation of diffuser flow using GAO-YONG turbulence equations

A two-dimensional incompressible diffuser flow was numerically simulated employing no staggered grid arrangement and incompressible SIMPLE method to solve GAO-YONG turbulence equations.The problem of checkerboard prediction of pressure was cured by evaluating the cell face velocities by the momentum interpolated principle.In order to improve the calculation precision,an orthogonal body fitted coordinate system was selected and a second-order QUICK discretization for the convective part was used.The calculation results such as velocity profiles and friction coefficients are finely close to the experimental data and better than the results of BL(Baldw-Lomax) model.It shows the GAO-YONG turbulence equations can predict the real turbulent flow with pressure gradient well without using empirical coefficients and wall functions.The calculation proves that it is important to the GAO-YONG turbulence equations for simulating adverse pressure gradient flow to introduce the effect of mean pressure gradient into energy equation which describes the characteristic length scale of the turbulent flow.