A new simplified numerical approach for shape design of underwater wings

This paper presents a new simplified numerical approach (SNA) for predicting hydrodynamic data of underwater wings (UWs). Instead of full three-dimensional (3D) flow field analyses, SNA combines Vortex Lattice Method (VLM) and several two-dimensional Reynolds-Average Navier-Stokes (2D RANS) simulations of wing sections to gain results. Hence, SNA shows a remarkably lower computational cost than higher-fidelity methods such as 3D RANS. Moreover, SNA shows good agreements with 3D RANS and experimental data. Thereafter, SNA is applied to shape optimizations of UWs for efficiency and accuracy. Two kinds of optimisation algorithms that include local and global finders are adopted in the optimiser. Searching behaviours of the two algorithms indicate that the problem is not proper to be solved by the local optimiser for its multimodality, while the global optimiser is more efficient. Furthermore, the final optimised wing has few wing-tip vortices and a smooth pressure distribution.