A new methodology to evaluate the flying shape of a sail

In the last years, many improvements have been made in sailing yacht design with particular regard to shapes, materials and building technologies. As racing yacht competitiveness is more and more growing, there is an increasing need for improvements of the sails and the hulls performances. In this context, the Computational Fluid Dynamics (CFD) method is increasingly used in the design process of the sails. Numerical simulations, nevertheless, are usually performed only on the design shape of the sail, without considering that the real flying shape of a sail greatly varies when subject to the normal working conditions. For these reasons, often, the real performances of a sail are very different from the ones estimated during the design phase. To overcome this problem, in the presented paper, an innovative methodology has been developed to evaluate the real (flying) shape of a sail during the design process. In particular, an iterative procedure has been setup to analyse, by means of a coupled CFD/FEM analysis, the fluid-structure interaction in a simplified model of a sail. The method allows to predict the real flying shape of a sail and, consequently, to optimize its performances.