Prediction of propeller non-cavitation noise by superimposing shifted sound signal from an isolated blade

The time-cost of the propeller non-cavitation noise prediction can be greatly reduced by the isolated blade method, which is validated via hybrid URANS and acoustic analogy, followed by the acoustic characteristics of propeller in time domain are analyzed. Firstly the sound of the E779A propeller operating in uniform inflow is predicted and validated. Typical periodic characteristic of the sound pressure distribution on each blade and the sound signal of the receiver is observed, and the result by the superimposing shifted sound signal from an isolated blade (isolated blade method) agrees well with that of by total blades, which validates the credibility of the isolated blade method in uniform inflow. Finally, the sound of a propeller running in the wake of submarine is predicted by the isolated blade method, and the result also agrees well with that of by the integration on total blades, which indicates that the isolated blade method is also applicable for the non-cavitation noise prediction of the propeller running in non-unifbrm inflow. The noise prediction of the counter rotating propeller, the pumpjet can also benefit from this.