AN EXPERIMENTAL STUDY ON MEASURING AND LOCALIZING PROPELLER NOISES BEHIND A BODY IN A CAVITATION TUNNEL

Abstract

The two major objectives of acoustical measurements in a cavitation tunnel are measuring the noise levels generated by rotating propellers behind a hull and localizing possible noise sources in order to reduce noise levels. Propeller noise measurement experiments were performed in MOERI cavitation tunnel at December, 2006. In order to put the propeller into cavitating conditions, a wake-generating dummy body was devised. In addition, ten hydrophones are put inside a wing-shaped casing in order to minimize the unexpected flow noise around hydrophone itself. After measuring both of the noises of the rotating propeller behind the dummy body and signals generated by a virtual source, respectively, the data were processed using the incoherent Bartlett processor to localize noises on the propeller plane. In this paper, we presented the measured noise spectrums and the localization results.