A Semi-empirical Modulation Model on Non-cavitation Noise of Underwater Counter-rotation Propellers

Underwater counter-rotation propeller non-cavitation noise has an obvious modulation characteristic which is due to the interaction of flow and blade, the modulation characteristic is critical for underwater target identification. Based on generalized acoustic analogy theory, a semi-empirical modulation model has been presented in this paper to describe its non-cavitation noise characteristics. Theoretical analysis has been verified by numerical simulation and cavitation tunnel experiment results. The numerical simulation has shown the directivity characteristic of typical modulated line-spectra. The experiment results have agreed with theoretical values. The modulation model of counter-rotation propeller is beneficial to the prediction modulation characteristics and identification of underwater high-speed vehicles.