Numerical Study of Sail Aerodynamics

Abstract

A boundary-element method to compute steady flows around a set of sails at close hauled conditions. (i.e., the wind is coming from upstream of the boat at a moderate angle of attack for the sails) is presented. It is based on a mixed potential-velocity formulation in order to solve the problem of zero thickness sail conditions. An iterative procedure is proposed to account for the interaction between sails; the shape of the wake of the leading sail is computed as and equilibrium stream surface in such a way that the plane wake assumption is not used. Numerical results are compared with tests conducted on isolated jibs and sets of jib and main sails in wind tunnels.