跨声速非等熵势函数方程的数值求解

基于动量方程的特点,本文将只与温度有关的“等熵密度”与熵的变化分离,而由散度型动量方程直接计算出气体经过激波的熵增。与经典势函数方程迭代,可以方便地求解非等熵跨声速流动。从对任意回转面叶栅的跨声速流动计算来看,这种非等熵势函数得到的激波位置可比等熵势函数前移1～2个网格,强度有所减弱,和试验结果较接近。由于各流线的熵不相等,对Kutta条件和出口边界条件作了修正。本文建议的方法也可用于计算流函数的熵增。

NUMERICAL COMPUTATION OF TRANSONIC NON-ISENTROPIC POTENTIAL EQUATIONS

Based on the analysis of the momentum equations and the non-isentropic flow,an "isentropic density" pt which is computed according to the isentropic relation and is dependent on the temperature only is separated from the entropy variation and the entropy increase across the shock may be directly calculated from the momentum equations in the divergent form.Iterating it with the classical potential equation may solve the non-isentropic transonic flowfield conveniently.It is seen from the calculations of transonic cascade flow on the surface of revolution that the shock in the non-isentropic calculation is placed further upstream and weaker compared to the classical potential solution.In the calculation,the effect of entropy increase on the Kutta condition and the outlet boundary condition is considered.