Objectives To suppress hydrodynamic noise from the source, a noise reduction method for pump-jet propulsors based on porous media is proposed.

Methods By replacing the metal leading edges of the stator blades of the pump-jet propulsor with porous materials, the interference between the blade wake and the inner wall of the duct can be effectively modulated, thereby reducing wall pressure fluctuations. Large eddy simulation (LES) combined with acoustic analogy analysis is employed to conduct flow and noise control analysis based on the porous leading edges of the stator blades. The modulation mechanisms of the porous media on the flow field and the noise suppression effect are investigated, and the influence laws of different property parameters, such as porosity and advance coefficient, on hydrodynamic noise control are obtained.

Results Comparative results show that the modulation effect of the porous leading edges on the stator effectively reduces the low-frequency sound pressure level components on the duct wall and the far-field radiation noise, with a maximum reduction of 5.52 dB in the sound pressure level of the pump-jet propulsor in the direction perpendicular to the rotation axis.

Conclusions The research findings can provide a reference for the flow and hydrodynamic noise control of pump-jet propulsors.