An application of dereverberation and multiplicative beamforming techniques for imaging noise sources generated by boat engines

Abstract

This paper demonstrates the application of a dereverberation algorithm for localizing noise sources emitted from two-stroke boat engines in three dimensions domain. The engines considered have a maximum RPM of 1500 and 1200 cc. It is important to note that these engines are operated with both petrol and CNG. The investigation primarily focuses on the noise generated under various loading conditions and aims to differentiate the noise characteristics between petrol and CNG engine operations. The dereverberation algorithm is applied to enhance the accuracy of noise source localization in this study, it involves filtering an approximate optimal window width to retain data related to the direct field while removing reflections through multiplication with an appropriate Hanning window. The analysis showed that the dereverberation algorithm effectively improves the imaging source map compared to conventional beamforming maps in the 3-D domain. To compute the beamforming output, data has been recorded from five different sides of the engine, and the multiplicative beamforming technique is employed. The findings highlight the significance of dereverberation and multiplicative beamforming techniques in accurately localizing noise sources in boat engine applications.