CAVITATION INDUCED HULL SURFACE PRESSURES--MEASUREMENTS IN A WATER TUNNEL
This paper discusses the practical aspects of testing model propellers in cavitating conditions behind dummy sterns or wake simulators in the No. 2 water tunnel at the National Maritime Institute. The importance of the propeller operating conditions, the production of the correct nominal axial wake and, in particular, the bubble nucleus spectra, are all considered. The methods used for measuring pressure fluctuations are discussed, and examples of the fluctuating pressures measured on the stern of a model of a seagoing container ship at different speeds are given. Large pressure fluctuations at frequencies of twice the blade rate and higher have been identified as being caused by vortex bursting or breakdown. This phenomenon is associated with the propeller tip trailing vortices reacting with the axial wake peak commonly found on some single screw vessels. It is concluded that small quantities of air injected into the vortices can be used to reduce or eliminate these pressures.
- Conf. paper reprint; Paper presented at Symposium on Propeller Induced Ship Vibration, London, December 1979
- English, J W
- Publication Date: 1980
- Features: References;
- Pagination: 18 p.
- TRT Terms: Cavitation noise; Hulls; Propellers; Vibration; Water tunnels
- Old TRIS Terms: Hull vibration; Propeller induced vibration
- Subject Areas: Marine Transportation; Vehicles and Equipment;
- Accession Number: 00661186
- Record Type: Publication
- Source Agency: Maritime Technical Information Facility
- Files: TRIS
- Created Date: Jul 21 1994 12:00AM