Flow Patterns and Aerodynamic Characteristics of a Wing-Strake Configuration

Abstract

Surface oil flow visualizations, force tests, and pressure measurements were conducted at low, transonic, and supersonic speeds. Four flow patterns on a wing with strake at low speed have been found. The flow on the wing upper surface is affected and controlled by the formation, development, and breakdown of the strake vortices. The differences in flow patterns are reflected in the force and moment results. The lift increment results from the effect of the strake vortex not only on the inner panel but also on the outer panel. The nonlinear variations of the pitching moment are discussed. The lift increment is decreased with an increase in Mach number at transonic speeds, primarily because the flow over the wing without strake changes from leading edge separation to leading edge attached flow with shock-induced separation. An increase in the lift-drag ratio is due to the lift increase at low speeds and the drag decrease at supersonic speeds.