Multiobjective Optimization of an IACC Sailing Yacht by Means of CFD High-Fidelity Solvers

Performance differences in box rule racing yachts, such as the International America's Cup Class (IACC), have progressively decreased, and the gap between the winner and the loser is on the order of a percentage point. Performances are also heavily influenced by the measurements rules, and the best hull is not the faster one, but the one that is properly located into the class rules: to realize improvements becomes more difficult. Numerical optimization techniques could help the design team by identifying the best course of action for improving the design. However, they must to fulfill two major requirements: reliability and efficiency. The first point is obtained by applying high-fidelity CFD solvers, based on an accurate physical model, like RANSE solvers. The second one, is achieved by not applying popular algorithms for local optimization, then adopting Global Optimization (GO) techniques. In this context, two different multiobjective optimization problem are formulated and solved. The outcome of these process is a suite of optimal solutions. In this way, the design team is not forced to accept a single final solution, but will be able to evaluate the trade-off between the different alternatives, selecting the one that is judged to be the best compromise among all the requirements.