Aerodynamic force and power for flapping wing at low reynolds number in ground effect

In the development of MAVs, small sized flapping wing designs mimicking insects have appeared recently and lot of studies have been carried out for various aspects of insect flight. The study of aerodynamics of ground effect is an important venue. In this paper CFD studies has been done to simulate the ground effect in hover flight for a rectangular wing. Various heights from very near to the ground till free stream condition where the ground effect is absent are investigated. Incompressible 3D NS equations are numerically solved and results are presented. Aerodynamic vertical force and aerodynamic power variation has been presented. The study indicates that during hover very near to the ground, average vertical force during a wing beat cycle increases largely as compared to its free stream condition in the absence of ground effect. For the typical case taken a 26% increase in average cycle vertical force and 11% decrease in average specific power is noted near the ground. Maximum vertical force increase is found below three quarters of wing length distance from the ground. The ground effect on aerodynamic force or power vanishes after 2.5 times the wing length height above the ground.