Efficient Method to Predict Rotor Noise Scattered by an Axisymmetric Body

Abstract

This paper presents an efficient method for predicting noise radiated from rotating sources and scattered by an axisymmetric body, in which a frequency-domain numerical method and a null-field method are employed to compute the acoustic radiation and scattering phenomena, respectively. The novelty of the present research is that an advanced method is proposed to locate fictitious interior observers inside the scattering surface, contributing to that the incident acoustic pressure received by the fictitious interior observers can be efficiently computed. Numerical cases show that the developed method ensures high computational accuracy and significantly improves the computational efficiency compared with existing methods, showing an appealing application potential in efficiently predicting rotor noise scattered by the shaft and casing. Parametric studies are carried out to investigate the effects of the hub–tip ratio and the rotating frequency on a rotor noise scattered by a hub.