非定常流动计算的混合时间推进方法研究

结合ADI方法的二阶时间精度特性和高斯-赛德尔迭代法的良好收敛性特性,提出了一种ADI-高斯-赛德尔混合迭代格式,应用该格式,对NACA0012翼型的跨声速俯仰振荡进行了EULER方程求解,空间离散格式采用ROE’S FDS格式,计算结果与实验及成熟的LUSGS双时间步迭代方法计算结果进行了分析比较。计算结果表明,该格式精度能达到LUSGS双时间步迭代方法完全收敛的二阶精度,且该格式精度对内迭代次数的依赖性较低。分析表明,本文提出的方法具有较高的精度和较好的收敛性。

A hybrid time stepping scheme for calculating unsteady flows

A new hybrid time stepping scheme which is the combination of ADI scheme and Gauss-Seidel iteration method is proposed in present work.This scheme keeps the characteristic of second order time accuracy of ADI scheme and good convergency of Gauss-Seidel iteration method.To investigate its accuracy and convergency,two computational tests of inviscid flows around NACA0012 airfoil in forced pitching up and down are made.In all computations,Roe's FDS scheme is used to discritize inviscid flux terms.Computational results reveal that the proposed method has normal second order accuracy which matches the accuracy of fully converged dual-time LUSGS scheme result.And,computational result comparison of different number of subiterations shows that the accuracy of the proposed scheme doesn't depend on the number of subiterations.