ROTOR NOISE INTERFERENCE MECHANISMS FOR SIDE-BY-SIDE CO-ROTATING CONFIGURATIONS

Abstract

This study investigates the aeroacoustic effects of phase synchronization between co-rotating propellers in sideby-side configurations. Space-time Proper Orthogonal Decomposition (POD) is applied to pressure fluctuations to separate tonal and broadband components, enabling detailed analysis of the acoustic interference phenomena. Experimental results demonstrate that synchronization significantly influences the tonal component, highlighting distinct regimes of constructive and destructive interference at different rotor phase delays. Specifically, the analysis reveals a notable reduction in noise amplitude at certain phase shifts, particularly affecting the second harmonic. An explanation of this scientific outcome is provided and illustrated schematically. Additionally, probability density functions indicate clear changes in the statistical characteristics of pressure fluctuations due to rotor synchronization, reinforcing the effectiveness of the decomposition method. These findings confirm the potential of rotor synchronization as an efficient active noisecontrol technique capable of achieving substantial noise reduction