Camber and aerodynamic performance of compliant membrane wings

We present a self-consistent theory to predict the behavior of compliant membrane wings subject to aerodynamic loads. The theory incorporates the Young-Laplace equation to treat nonlinear deformation of the membrane at low angles of attack and uses a potential flow model to estimate the aerodynamic load associated with the thin wing. The model is able to account for finite span wings as well as to predict the occurrence of lift hysteresis, in which a lightly pretensioned membrane adopts camber at zero angle of attack. The theory is compared with results from numerical simulations that couple the structural deformation of the membrane with the fluid flow and also with experimental measurements of free tip and supported tip membrane wings tested over a range of aeroelastic conditions. Predictions of camber, lift and vibrational frequency are in good general agreement with both numerical and experimental observations.