Method to Control Unsteady Force of Submarine Propeller Based on the Control of Horseshoe Vortex

The submarine propeller works in the submarine wake with severe circumferential nonuniformity, which causes the hydrodynamic force to act on the blade. This results in severe oscillation with the rotation of the propeller and impairs the hydrodynamics and noise performance of the submarine propeller. The horseshoe vortex generated at the hull-appendages junctions of the submarine has important influence on wake uniformity. In the present study, the state of the submarine horseshoe vortex is analyzed and a new method of vortex control baffler is presented. The aim is to weaken the horseshoe vortex. Based on the wind tunnel experiment and numerical simulation on the submarine model, the vortex control baffler can decrease the strength of the submarine horseshoe vortex and improve the uniformity of the submarine wake. Vortex control bafflers adapted for the fully appended SUBOFF model are designed, and the unsteady force of three kinds of propellers functioned after the SUBOFF model is calculated numerically. The results show that although the skew angle and blade number are different, the amplitudes of the unsteady force acting on the blades of all three propellers decreased by 50% to 80% due to the effects of the vortex control baffler.