High fidelity computational simulation of a membrane wing airfoil

Computations and analysis for a two-dimensional flexible membrane wing airfoil are presented. A well-validated, robust, sixth-order Navier–Stokes solver is employed coupled with a membrane structural model suitable for the highly nonlinear structural response of the membrane. A low Reynolds number, Re = 2500 , consistent with MAV flight is chosen for the majority of the calculations. The most notable effect of the membrane flexibility is the introduction of a mean camber to the membrane airfoil. A close coupling between unsteady vortex shedding and the dynamic structural response is demonstrated. The dynamic motion of the membrane surface is also shown to significantly alter the unsteady flow over the membrane airfoil at high angles of attack. The coupling of this dynamic effect and the mean camber results in a delay in stall with enhanced lift for higher angles of attack. Exploratory computations investigating the effects of angle of attack, membrane rigidity, membrane pretension and Reynolds number on the membrane airfoil response are also presented.