非流线体分离流动态载荷的数值模拟方法研究

The Numerical Method of Unsteady Airload for Separated Flow Around Any Bodies

以圆柱绕流为研究对象 ,针对圆形边界 ,采用O型网格对流场进行离散 ,用二阶精度的中心差分有限体积法作空间离散 ,用二阶精度的中心差分处理时间问题 ,用双时间方法求解了二维非定常Navier-Stokes方程 ,系统研究了计算方法对收敛精度、时间步长和网格数量的依赖性。计算结果表明 ,对于长时间历程的非定常问题 ,虽然双时间方法收敛性很好 ,但对于分离流而言 ,时间步长的选取并非没有限制 ;每一步伪时间的推进中 ,收敛精度也有要求 ;而要模拟圆柱分离流的非线性气动力现象 ,计算网格至少要达到 2 6 0× 80的数量。

The separated unsteady flow around a circle is simulated in this paper based on the Navier Stokes equations. The O type grid is generated and the finite volume method is used for space discretization. A dual time scheme is used to solve the unsteady problem. The effects of the time step, convergence euiteuion, and the grid number on the results are investigated. It is shown that the time step for the discussed problem must be less than 0.1 (nondimensional time), the maximum residual should be less than 10 -5 , and the grid must be more than 260×80 then the nonlinear aerodynamic force can be simulated.