A method is presented for imaging rotating broadband sources with a microphone array. The microphone array rotates virtually with the same angular frequency as the source such that the pressure data are mathematically transformed into a rotating reference frame and the influence of the moving source (Doppler shift) is compensated. In contrast with other works, this method works completely in the frequency domain by using the spherical harmonic series expansion method to calculate a modified free-space Green function in the rotating system. An analytical solution for the sound radiation from the rotating sound source, which considers motion compensation and a uniform subsonic axial flow, is deduced. Simulations on a rotating point source considering axial flow are performed. Measurements with a fan are examined for different frequencies with standard delay and sum beam-forming and high-resolution algorithms.
Imaging of Broadband Noise from Rotating Sources in Uniform Axial Flow
AIAA Journal ; 55 , 4 ; 1185-1193
2016-11-02
9 pages
Article (Journal)
Electronic Resource
English
Imaging of Broadband Noise from Rotating Sources in Uniform Axial Flow
Online Contents | 2017
|Imaging of Broadband Noise from Rotating Sources in Uniform Axial Flow
Online Contents | 2017
|