Ground Viscous Effect on 2d Flow of Wing in Ground Proximity

Viscous effect of wing in ground effect in wind tunnel test was investigated numerically. Ground settings in wind tunnel test were simulated by specifying different ground boundary conditions in CFD. It was revealed for fixed-ground based wind tunnel test that: boundary layer developed from the ground deforms effective ground surface and introduces a decreased effective ground clearance; a sharp increase in boundary layer thickness and adverse pressure gradient are captured, which is attributed to deceleration of flow under the leading edge; a separation bubble on ground forms in very small ground clearance and large angle of attack, which helps air flow around the leading edge and delays the stall; measured aerodynamics in fixed-ground based wind tunnel test are not accurate due to ground viscous boundary layer flow; ground viscous flow simulation is of great importance in indepth studies on ground effect. The results obtained will be useful in developing and evaluating wind tunnel tests and studies for wing in ground effect craft.