Application of the Vortex-Lattice Method to High-Angle-of-Attack Subsonic Aerodynamics

The vortex-lattice method for general, unsteady, incompressible aerodynamics is described. This method can treat multiple lifting surfaces operating in close proximity, fully accounting for interference. It is not limited by planform, camber, twist, or maneuver as long as separation occurs only along known lines and vortex bursting does not occur near one of the lifting surfaces. Steady flows can be treated efficiently as special cases of uniform motion. Several examples are presented as a partial illustration of the range of problems that can be treated. These include steady and unsteady flows over rectangular and delta wings, a numerical simulation of the wingrock phenomenon, and steady and unsteady interference among two canards and a wing. In the numerical simulation of wingrock, the equation governing the motion of a delta wing mounted on a free-to-roll sting is integrated numerically by a predictor-corrector method with the aerodynamic roll moment being supplied by the vortex-lattice method. This numerical sol-ution determines the motion of the wing and the flow-field simultaneously, fully accounting for the aerodynamic/dynamic interaction. The numerical solutions are in good agreement with available experimental data.