Analysis of sound measurements inside a finite length ducted rotor system.

Abstract

The sound generated by a ducted rotor system leads to a complicated acoustic field inside the duct. The source can have both broad‐band and tonal sound features. The interior Green’s function will add additional complexity due to the cut‐on modes and finite‐length (organ pipe) effects. In this study, a simple ducted rotor was considered experimentally and analytically in order to obtain observations and predictions of these features. The results will be an important component of modeling the structural vibration in systems where the rotor operates in an elastic shell.