Investigation of the position of noise sources in a turbulent subsonic jet using the beamforming technique

Abstract

The position of the noise sources is the most important information in aeroacoustic research. This is especially true for the noise of a turbulent jet, in which noise is generated by many vortices of various scales interacting with each other. This leads to the fact that noise sources at different frequencies are distributed inside the jet. This information is especially important, for example, for the development of computational shielding models. There are a series of methods to identify the position of noise sources of different frequencies in the noiseproducing region of the flow. The most universal among them today are methods based on conducting acoustic measurements using microphone arrays. Acoustic measurements of the noise of the expiration of an air subsonic turbulent jet were carried out in a anechoic chamber at the PNRPU. Two planar beam microphone arrays with the same number of microphones and their different locations in the plane of the array were used. Postprocessing was carried out using the beamforming technique. The results obtained in this study were compared with the expression for the Strouhal number. It was found that the position of the noise sources in the jet is quite close to the calculated one.