Analysis of Stalled Airfoils by Simultaneous Perturbations to Viscous and Inviscid Equations

Abstract

An iterative viscous-inviscid interaction method is presented for predicting the pressures, forces, and moment of an arbitrary airfoil with massive turbulent separation in incompressible, steady flow. In each iteration cycle, the viscous-inviscid interaction is explicitly modeled by a mathematical expansion to a boundary-layer method and a panel method. Linear terms are retained to account for the complete first-order coupling between the viscous and inviscid equations. The system of linear, algebraic equations is solved for the perturbation to the displaced streamline geometry. Example calculations are presented that demonstrate consistently rapid convergence and good agreement with wind-tunnel data.