Measurement of propeller-induced cavitation noise for ship identification

Abstract

Acoustic cavitation noise caused by propeller is used in many underwater applications as one of the ships noise signatures. This paper reports characterization process done by measuring the cavitation noise generated by a propeller in a cavitation tunnel. The cavitation tunnel used for the measurement is of the K16B type belonging to the Indonesian Hydrodynamic Laboratory, Surabaya, Indonesia. The experiment is done using a B-series four-blade bronze propeller (diameter 23cm) using a hydrophone placed in the tunnel at window section (60x90)cm2 of the measurement section (400x85x85)cm3. Some of the solutions to get accurate and reliable measurement results include calibration measurement and minimizing acoustic noise system and environment. Preliminary process has been done to analyse the characteristics of the measurement results in the time-frequency domain, with the objective being to detect when and which type of cavitation noise occurs in any kind of condition. Measurement outcomes in the form of acoustic data signals are obtained in different conditions by varying the water pressure, flow velocity and propeller speed rotation.