An Iterative Algorithm for the Optimal Control of Propeller Noise Through Synchrophasing

This paper presents an iterative scheme for identifying the optimum synchro phase angles to minimise total sound power radiation from a number of co-planar and co-rotating synchrophased propellers. Numerical results are presented to illustrate the effectiveness of the control algorithm and to explore the behaviour of the optimal synchrophase angles and associated sound power reduction. It is shown that there exists a condition based on the relative positions of the propellers for which sound power is minimised when adjacent propellers are 180° of phase. At all other angles, however, the optimum set of optimum phase angles becomes a function of their separation angles. This behaviour is investigated analytically for the three-propeller case.