Aeroacoustic Source Identification Using Generalized Inverse Beamforming

Aeroacoustic source identification poses some challenges to the conventional techniques such as the conventional beamforming. The challenges can be summarized as the distributed nature of the aeroacoustic sources, in coherent or incoherent radiation, with multipole radiation characteristics. In order to cope with these difficulties, the Generalized Inverse Beamforming (GIB) is adopted. This method allows the simultaneous identification of compact or distributed, coherent or incoherent, mono or multipole sources, with a reduced number of sensor signals. The method is applied to an aeroacoustic test using a simple geometry as obstacle in a low Mach number jet. The result focuses on the dipole formation on the circular cylinder surface. Convection and refraction influence are included in the identification using a simplified approach for the retarded time calculation. Equivalent pressure mappings are generated to help visualization of the radiation field. This work investigates the performance obtained on the use of the GIB method on this simple aeroacoustic source identification problem.