Numerical Simulation on Unsteady Flow Around an Oscillating Airfoil with Ground Effect

To simulate the unsteady flow around an oscillating NACA0012 airfoil with ground effect,the Euler equations are solved and sliding mesh is used,then the dynamic characteristics are investigated numerically at different heights between airfoil and ground,and the change of lift and moment hysteresis loops are analyzed,finally combined with small amplitude oscillation method,all the dynamic derivatives at different heights are calculated. The result show that ground effect has influence on both steady and unsteady flow fields,the lift hysteresis loop changes smaller as the height lower,while the moment dynamic derivative become bigger,which means making loss on longitudinal dynamic stability. The ground effect should be considered during unsteady aerodynamic research.