Numerical study on hydrodynamic performance of an underwater propulsive wing propulsor

Abstract

The propulsive wing has an excellent aerodynamic performance due to boundary layer control. When propulsive wings are applied to unmanned underwater vehicles (UUVs), high hydrodynamic forces in both the horizontal and vertical directions significantly enhance UUV maneuverability. To investigate the hydrodynamic performance of a propulsive wing propulsor (PWP), the underwater flow field of the PWP is numerically simulated. The hydrodynamic performance of the PWP is subjected to comprehensive investigation in terms of its hydrodynamic efficiency, unsteady force, and wake evolution. A three-dimensional simulation is undertaken to briefly analyze spanwise effects on PWP hydrodynamic performance. The results show that the PWP delivers an excellent hydrodynamic performance with high hydrodynamic coefficients, where power load and propulsive efficiency before stall reach 4.4 and 0.23, respectively. The convergence of blade-shedding vortices at the bottom of the deflector provides vortex-induced lift but leads to high-frequency and high-amplitude fluctuations in PWP hydrodynamic forces. The amplitudes of the fluctuations are closely correlated to the vorticities of the blade-shedding vortices. The three-dimensional simulation results show that, before stall, spanwise effects on PWP hydrodynamic forces and the wake structure are limited.