The aerodynamics of a sailing yacht with different sail trims are presented, derived from simulations performed using computational fluid dynamics. A Reynolds-averaged Navier–Stokes approach was used to model sixteen sail trims first tested in a wind tunnel, where the pressure distributions on the sails were measured. An original approach was employed by using two successive simulations: the first one on a large domain to model the blockage due to the wind tunnel walls and the sails model, and a second one on a smaller domain to model the flow around the sails model. A verification and validation of the computed aerodynamic forces and pressure distributions was performed. The computed pressure distribution is shown to agree well with the measured pressures. The sail surface pressure was correlated with the increase of turbulent viscosity in the laminar separation bubble, the flow reattachment and the trailing edge separation. The drive force distribution on both sails showed that the fore part of the genoa (foresail) provides the majority of the drive force and that the effect of the aft sail is mostly to produce an upwash effect on the genoa. An aerodynamic model based on potential flow theory and a viscous correction is proposed. This model, with one free parameter to be determined, is shown to fit the results better than the usual form drag and induced drag only, even if no friction drag is explicitly considered

The work presented in this paper focuses on the CFD application of large eddy simulation (LES) and detached eddy simulation (DES) to the prediction of the flow around and past an International America's Cup Class yacht keel model.

In this paper, we present ADONF, a new numerical simulation platform for viscous flows. This platform is developed and validated to compute analysis, design and optimization of real flows around complex sails configurations through a large number of automated Reynolds Averaged Navier-Stokes (RANS) simulations. We illustrate the ability of ADONF to search for robust, high performance, optimized fluid flows, in the field of the aerodynamic of sailing boats. Results presented focus on the optimization of the design and trimming of interacting sails because it is a question of major interest for many competitive sailors. Because ADONF is based on Navier-Stokes equations in RANS or URANS formulations, sail shape and trimming optimization in upwind and downwind sailing conditions may be addressed as will be shown. For future applications, it will be possible to extend and apply ADONF to hydrodynamic of sailing boats or any other fields in fluid mechanics governed by Navier-Stokes Equations.