Beamforming correction for the singular problem in identifying rotating sources with non-uniform directivity

Abstract

Identification of rotating sources with non-uniform directivity has been paid much attention in the field of aeroacoustic measurements over recent years. Singularities may be produced on the source map by using the rotating source identifier based on the multipole model due to zeros of the directivity function. A correction method is proposed to remove the influence of source directivity on source imaging and restrain the singular problem. De-Dopplerized microphone signals are transformed to the frequency domain and deconvolved with transfer functions to compensate for directivity functions. Numerical simulations, as well as experiments using rotating dipole loudspeakers, were conducted to verify the proposed method. It is demonstrated that the method is suitable for rotating sources with arbitrary orientation and works well under a high level of background noise. Positions and strengths of sources are estimated more accurately than traditional algorithms.

Real-time reconstruction of unsteady rotating forces acting by rotor blades in moving medium

“…The identification methods for the static aeroacoustic sources are usually not suitable for the identification of rotating aeroacoustic sources [25]. At present, many methods have been proposed to perform rotating aeroacoustic source identification [26][27][28][29], such as the classic de-Doppler techniques [30], virtual rotating array method [31] and mode decomposition methods [32]. However, these methods are usually based on the static/quiescent medium assumption.…”

An Improved Time-Domain Inverse Technique for Localization and Quantification of Rotating Sound Sources

“…Ma et al [15] analyzed the ghost contribution in the TRB due to the Doppler effect in virtue of a detailed theoretical derivation, and provided an effective strategy to compensate the Doppler effect in the TRB. Pan et al [16] developed a correction method for the TRB to restrain the singular problem in identifying rotating sources with the non-uniform directivity. In recent years, deconvolution algorithms were subsequently used to improve the spatial resolution of the TRB [17][18][19][20][21].…”

Spatial and temporal reconstruction of unsteady rotating forces through an inverse acoustic method

“…However, most of these beamforming methods are based on either static dipole sources [21][22][23][24][25][26][27] or moving monopole sources [28][29][30][31] and have been rarely used for the identification of rotating loading sources. Recently, Pan et al, [32] developed a beamforming correction method in the frequency domain to identify rotating loading sources. Chen et al, [33] proposed a beamforming method in the time-frequency domain based on a moving dipole source formulation and obtained acoustic imaging results at different frequencies from an array located on the side of a propeller.…”