Abstract :
A nonsingular integral equation is developed for thin airfoils with the Dirichlet boundary condition. Both singular and near singular kernels which accompany the original integral equation are flattened out. After such regularizations, the difficulty in the numerical quadrature is greatly reduced. A program with an arbitrary-order integral formulation becomes available in the present approach. Two kinds of airfoils, the van de Vooren and Joukowski airfoils, are analyzed for demonstration in this paper. In comparison with the results from constant-doublet methods, the results from the proposed methods are shown to match the analytic solutions excellently.