Derivative-free global design optimization in ship hydrodynamics by local hybridization

A derivative-free global design optimization of the DTMB 5415 model is presented, using local hybridizations of two global algorithms, DIRECT (DIviding RECTangles) and PSO (Particle Swarm Optimization). The optimization aims at the reduction of the calm-water resistance at Fr = 0.25, using six design variables modifying hull and sonar dome. Simulations are conducted using potential flow with a friction model. Hybrid algorithms show a faster convergence towards the global minimum than the original global methods and are a viable option for design optimization, especially when computationally expensive objective functions are involved. A resistance reduction of 16% was achieved.