用Newton子迭代方法计算前飞旋翼粘性绕流

Numerical simulation of the viscous flow past a helicopter rotor in forward flight using newton-like sub-iterations

通过求解Navier Stokes方程数值模拟了直升机旋翼前飞非定常流场。为了同时保证计算的时间精确性和计算效率 ,时间推进格式采用了双时间推进方法。在该方法中 ,子迭代过程由十分高效的LU SSOR方法完成 ,且使子迭代过程成为Newton子迭代。空间上应用中心平均的有限体积法进行离散。为了模拟前飞桨叶间的相对运动 ,网格布局采用了运动嵌套网格方法。应用本文方法对一悬停流场进行了数值计算 ,计算结果与实验吻合较好 ;尽管缺乏实验数据的验证 。

A new implicit numerical method has been developed to simulate the viscous flow past a helicopter rotor in forward flight by solving Navier Stokes equations. In order to gain both time accuracy and computational efficiency, a fully implicit method (dual time stepping method) has been developed, in which Newton like sub iterations based on LU SSOR scheme are included. The cell centered finite volume method is used as the spatial discretization method. The moving overset grid method is employed to account the relative motion among the blades which are rotating, cyclic pitching and cyclic flapping. To build the connection among the overset grids quickly, a highly automatic and very efficient method based on Hole Map and Inverse Map is implemented. Comparison of the numerical results for a lifting hovering case shows good agreement with the experimental data. Although lacking experimental verification, the numerical result of the lifting forward flight case is reliable.