Detecting Inception of Hydrodynamic Cavitation Noise of Ships using Quadratic Phase Coupling Index as an Indicator

M. Sandhya; K. Rajarajeswari; P. Seetaramaiah

doi:10.14429/dsj.65.7885

M. Sandhya Naval Science and Technological Laboratory, Visakhapatnam-530 027
K. Rajarajeswari VITAM College of Engineering, Visakhapatnam- 531 173
P. Seetaramaiah Andhra University, Visakhapatnam-530 003

DOI: https://doi.org/10.14429/dsj.65.7885

Keywords: Marine propellers, cavitation, bispectrum, bicoherence, higher order spectra, radiated noise, quadratic phase coupling

Abstract

There is ever increasing interest in underwater noise control onboard ships as part of concerted efforts to reduce ship’s radiated noise. Reduction of radiated noise is considered important as it will affect the performance of hydro-acoustic systems such as sonars, echo sounders, towed systems, etc. Out of three major sources of noise onboard ships, viz., machinery, propeller, and hydrodynamic noise, propeller noise is considered a major source beyond certain speed at which propellers cavitate produces cavitation noise. The inception speed of propeller cavitation is generally accompanied by sudden increase in radiated noise level of 8-15 dB when measured using a hydrophone placed on the seabed. This paper attempts to establish the concept of quadratic phase coupling index as an indicator to detect inception of cavitation of ship propellers. This concept was tested on actual ship radiated noise data measured at sea for evaluating its effectiveness.

Defence Science Journal, Vol. 65, No. 1, January 2015, pp.53-62, DOI:http://dx.doi.org/10.14429/dsj.65.7885

Author Biographies

M. Sandhya, Naval Science and Technological Laboratory, Visakhapatnam-530 027

Mrs M. Sandhya received her BE (Electronics and Communications) from Andhra University and MTech (Radar and Communication) (Underwater Electronics) from IIT (Delhi) in 1990. Presently working as Additional Director at Naval Science and Technological Laboratory, DRDO, India. She has vast experience in the field of electronics of naval systems. Her research areas of interest are : Underwater torpedoes, autonomous underwater vehicle, signal processing and embedded systems among others.

K. Rajarajeswari, VITAM College of Engineering, Visakhapatnam- 531 173

Prof. (Mrs) K. Rajarajeswari received her BE, ME and PhD in the field of Electronics and Communication. She is presently Principal, Viswanadha Institute of Technology And Management, College of Engg. She conducted several National and International Conferences of repute and guided more than 20 PhD scholars in the field of Signal Processing. Her specialization is digital signal processing and wireless CDMA communication.

P. Seetaramaiah, Andhra University, Visakhapatnam-530 003

Prof. P. S. Ramaiah received his PhD in Computer Science and Systems Engineering from Andhra University in 1990. He is presently working as a Professor Emeritus in the department of Computer Science and Systems Engineering, Andhra University, Visakhapatnam. He has received DRDO’s Academic Excellency Award for the year 2011. He has published 45 journal papers, and presented 15 papers in international conference and 21 papers at national conferences. His areas of research include : Bio-electronics systems, safety-critical computing- software safety, VLSI and real time embedded systems.