A subsonic lifting surface theory for wing-in-ground effect (Q555661)

The authors generalize lifting theory to the case of wing-in-ground effect in subsonic flow. Solid ground and free surface are taken into account for a three-dimensional wing solved by lifting surface theory from an inviscid point of view. The wing is divided into a finite number of panels, and each of them is placed by horseshoe vortices. The aerodynamic behavior of a wing-in-ground effect is investigated. Numerical examples are given to study the influence of clearance and Mach number on the lift for wing-in-ground effect. This effect is significant while the ground clearance is small, no matter if solid ground or free surface is registered under the wing, as the lift increases dramatically. The wing-in-ground effect is significant while the clearance is small. With an increase in clearance, the effect becomes weaker.