不可压缩势流绕多段翼型流动的快速迭代解法

利用保角变换计算不可压缩势流绕翼型的流动,具有计算速度快和要求计算机内存小的优点,但主要用于单段翼型问题,而对于多段翼型,尤其是三段和三段以上的翼型则很难应用。本文在单段翼型的保角变换的基础上,提出了一种利用迭代算法计算任意多段翼型的不可压缩势流的绕流问题的方法。本文方法和目前常用的边界元法相比,具有计算速度快的优点。本方法还可进一步推广到考虑无粘流/边界层的迭代计算中。

A FAST-CONVERGENCE ITERATION SOLUTION OF INCOMPRESSIBLE POTENTIAL FLOW AROUNDMULTI-ELEMENT AIRFOILS

Use of conformal mapping for the solution of incompress-ible flow around airfoils possesses the advantages of short CPU time and small storage. However, it is difficult to use it for multi-element airfoils, especially for airfoils with or more than three elements. Based on the conformal mapping of single-element airfoil, a fast-con-vergence iteration solution for multi-element airfoils is given in the present paper. The total flow field is considered as the sum of the incom-ing parallel flow and the perturbed flows of each elements. The latter can be solved iteratively and the Kutta condition at the trailing edge of each element is included in the solution. The convergence of the method is rather fast and needs only 10-15 iterations.Compared to the widely used panel method, the CPU time for the present method for a four-element airfoil is about one third of the former one. The further application for the inviscid/viscous iteration is also possible.