Numerical Analysis of the High Skew Propeller of an Underwater Vehicle

A numerical analysis based on the boundary element method (BEM) was presented for the hydrodynamic performance of a high skew propeller (HSP) which is employed by an underwater vehicle (UV).Since UVs operate at two different working conditions (surface and submerged conditions),the design of such a propeller is a cumbersome task.This is primarily due to the fact that the resistance forces as well as the vessel efficiency under these conditions are significantly different.Therefore,some factors are necessary for the design of the optimum propeller to utilize the power at the mentioned conditions.The design objectives of the optimum propeller are to obtain the highest possible thrust,minimum torque,and efficiency.In the current study,a 5-bladed HSP was chosen for running the UV.This propeller operated at the stem of the UV hull where the inflow velocity to the propeller was non-uniform.Some parameters of the propeller were predicted based on the UV geometrical hull and operating conditions.The computed results include the pressure distribution and the hydrodynamic characteristics of the HSP in open water conditions,and comparison of these results with those of the experimental data indicates good agreement.The propeller efficiency for both submerged and surface conditions was found to be 67％ and 64％,respectively,which compared to conventional propellers is a significantly higher efficiency.