Investigation of Prestress-Dependent Aerodynamic Performance of a Double Membrane Sailwing

Abstract

This paper investigates the aerodynamic performance of a semiflexible membrane wing concept using twoway coupled fluid–structure interaction simulations. The sailwing concept consists of a rigid leading-edge mast, ribs, tensioned edge cables, and membranes forming the upper- and lower-wing surfaces. For membrane structures like the sailwing, the exact shape of the membrane surface in the absence of external loading depends on the prestress levels of both membranes and supporting edge cables. A form-finding analysis is used for calculating the equilibrium shape of prestressed membrane surfaces with no external loading. The exact shape of the sailwing in operating condition depends on the pressure distribution on the membrane’s surface, which itself depends on the wing’s shape and the structural parameters. For faster design space exploration, the fluid problem is modeled using an unsteady vortex panel method. Among all the factors influencing the fluid–structure interaction problem, the role of the prestress level is specifically investigated. A nonlinear dynamic analysis of the structural problem is performed using the finite element method. The influence of the wing’s flexibility on its aerodynamic performance and structural response is examined by changing the prestress level in the membranes. Aerodynamic characteristics of the membrane wing are compared with an equivalent conventional rigid wing. A higher lift slope for the membrane wing and improvement of the lift coefficient due to trailing-edge flexibility are observed.