Comparison of the Rotating Source Identifier and the Virtual Rotating Array Method

Abstract

The aim of this paper is to present two acoustic beamforming methods developed for rotating sources, namely the Rotating Source Identifier (ROSI) and the Virtual Rotating Array method (VRAM). These were applied onto a series of simulated test cases, and their behaviour was analysed. Both methods were able to localise the source reliably. However, the source strength was found to depend on the number or microphones when VRAM was applied. This phenomenon was quantified and an approximate formula was given providing the minimum number of microphones required to reach a certain amplitude error. Beamwidth and side lobe suppression were found to agree between the two methods, meaning that the way rotation is handled does not significantly affect the point spread functions. The computational cost of ROSI was two to three orders of magnitude higher than that of VRAM. The results show that both methods are applicable for the beamforming analysis of rotating sound sources. However, in case of VRAM, the number of microphones has to be chosen carefully to obtain reliable amplitude results.

An empirical model to determine lift and drag coefficients of cambered plates at moderate Reynolds numbers

“…In the future, the results can also be utilized for aeroacoustic purposes. Utilizing the drag coefficient, the frequency of profile vortex shedding can be determined, 8 and by means of supplementary phased array microphone measurements, 18,19 aeroacoustic phenomena can be investigated in detail.…”

Sound localization and quantification analysis of an automotive engine cooling module

“…An extensive comparison between VRA and ROSI algorithms has been conducted by Kotán et al [30], highlighting the increased computational cost of ROSI against the VRA method. Nevertheless, both techniques accurately predict the location and the strength of the rotating source.…”

An Extension of the Virtual Rotating Array Method Using Arbitrary Microphone Configurations for the Localization of Rotating Sound Sources

“…Various comparisons of the three methods have been conducted [9][10][11]. The resulting delay and sum beamforming output for source localisation have been found to be almost equal for all the methods.…”