Nonlinear aerodynamics of a two-dimensional membrane airfoil with separation

A chain model is proposed for solving the nonlinear problem of a single-membrane sail wing, eventually in the presence of elasticity and porosity. The presented results are compared with existing data. The model deals with extended ranges of slack and angle of attack effectively and evaluates the corresponding lift and tension coefficients. The model is also extended to partially separated flows. Nomenclature b = length of the element in the chain over chord b0 = initial length of the element over chord c = chord length CL = lift coefficient ACp = pressure difference coefficient, = (pv -pL)/q CT = tension coefficient, = T/qc k = stretch coefficient, = (