A hybrid numerical method to develop America’s Cup yacht appendages

Abstract

A method aimed at the development of an America’s Cup racing yacht bulb is developed and validated against experimental data. The method relies heavily on Reynolds Averaged Navier Stokes computational fluid dynamics (CFD) and also factors in gravitational and aerodynamics effects through the use of a Velocity Prediction Program. Initial extensive use of towing tank results is made to be able to validate the CFD solution and thus develop a solid ground for predictive work. Then, in order to narrow down the focus on bulb developments, decoupled hypotheses are made on the influence of the hull and free surface wave. The development of a detailed performance analysis chart of a known base bulb allows the use of a relatively small series of CFD simulations together with physical hypotheses to assess any given bulb performance relative to the known base. The discussion of the results on a specific development highlights the promises and limitations of the method; final full scale results are discussed and analysed as well.