Coupled Viscid-Inviscid Calculation Method for the Prediction of Unsteady Separated Flows over an Airfoil

摘要

A coupled viscid-inviscid aerodynamic model ADAM2 (Advanced Dynamic Airfoil Model in 2 dimensions) is utilized to predict separated and unseparated flows over airfoils in steady and unsteady motion. Calculation results include pre- and post-stall pressure distributions, lift and drag, and trailing wake geometries for airfoils with a constant angle of attack, sinusoidally varying angle of attack, and constant rate pitching to large angles of attack. The principal difficulty yet to be overcome is the detailed representation of the viscid-inviscid interactions in the immediate vicinity of the boundary layer separation point. A persistent feed-back effect has been observed in which the presence of the separated wake surface causes the position of the boundary layer separation point to move progressively toward the leading edge. 10 refs., 10 figs. (ERA citation 13:016688)