To improve the hydrodynamic performance and payloads assembly space of unmanned underwater vehicles, considering an unpowered underwater vehicle's main body as the research object, the minimum drag coefficient and maximal volume utilization rate as the objective functions was analyzed in this paper. An automatic computation and analysis process based on surrogate models was built in Isight. Two main body shape design schemes was compared in geometry and hydrodynamic performance. Taking the functional requirements of unpowered underwater vehicle into account, the rectangular streamline body is adopted. Samples were selected using the Optimal Latin Hypercube method and fitted by different approximation models, the model that meeting optimization need was obtained. The NSGA-II algorithm was adopted to solve multi-objective optimization and the Pareto solution set are given. Finally, an optimized design plan was selected after weighing, compared with the initial design, although the volume and volume utilization rate is reduced by 1.21%, 7.38%, respectively, but the hydrodynamic performance has been greatly improved, the pressure drag coefficient, friction drag coefficient and total drag coefficient is reduced by 65.5%, 3.22%, 23.05%, respectively. The optimization result is obvious, which provides a basis for the main body design of the unpowered underwater vehicle.

This study is published in 2020 3rd International Conference on Unmanned Systems (ICUS)