Free Motion Simulation of a Sailing Yacht in Up-Wind Condition with Rough Sea

Abstract

Advanced CFD techniques make it possible to investigate the complex interaction between aerodynamics, hydrodynamics, and rigid-body motion in sailing yachts operating in realistic sea conditions. Free-motion simulations that couple unsteady multiphase flow models with six-degree-of-freedom dynamics enable the evaluation of yacht performance in up-wind sailing under rough sea states. This integrated approach combines turbulence modeling, volume-of-fluid wave representation, and dynamic mesh handling to capture both sail aerodynamics and hull–wave interactions. The methodology allows detailed analysis of boat motions, thrust generation, hydrodynamic loads, and their correlations with velocity, heel, and pitch, providing insight into off-design behavior that cannot be obtained from simplified or steady configurations. Although computationally demanding, such simulations offer a powerful tool to support yacht design and performance assessment, improving the understanding of real operating conditions and enabling more informed engineering choices in high-performance sailing applications.