Large yacht resistance reduction by hydrodynamic multi-objective shape optimization

Abstract

ABSTRACT This paper presents the results of the hydrodynamic optimization of a large yacht concept design that is meant to be used as a reference for future buildings. The optimization framework is used to improve the calm water resistance performance of a generic baseline design while satisfying a set of geometrical constraints. The shape of the hull is modified according to a geometrical interpolation approach where two shapes are combined to obtain a third design. The search towards the optimum is driven by a global convergence, multi-objective, genetic algorithm where the resistance of each candidate is evaluated by a Boundary Element Method. The final optimal design is then verified by means of a high-fidelity Reynolds Averaged Navier–Stokes technique, preliminary validated against available experimental data. The obtained results show the strong influence of the stern shape of the hull on the final resistance performance, highlighting the effects of the pressure recovery due to a so-called S-shape bottom. The bow shape is modified consistently to fulfil the geometric constraints and to further improve the resistance performance by inducing a positive interference effect on the generated wave pattern.