PREDICTION OF LINE-SPECTRUM NOISE INDUCED BY UNDERWATER VEHICLE CONTRA-ROTATING PROPELLERS

摘要

Line-Spectrum noise of contra-rotating propellers has constructed the main part of the radiated noise of underwater vehicles. The line-spectrum noise of the contra-rotating propellers is due to the interaction between the wake of the vehicle and the contra-rotating propellers, and the interaction between fore and aft propeller. Based on a combination of the lifting surface theory and acoustic techniques, the prediction method of line-spectrum noise is presented in this paper. Theoretical calculation method, characteristics and numerical prediction of the line-spectrum noise are detailed in this paper. The effect of different wake and different gap between fore and aft propeller on the propeller noise is also studied by numerical method. The agreement of predicted results compared with existing experimental data is quite satisfactory. Therefore, the methods are to have important values for performance prediction of the vehicles, identification of the noise sources and acoustic design of contra-rotating propellers, etc.