The Influence of Hydrofoil Oscillation on Boundary Layer Transition and Cavitation Noise.
Abstract
Significant effects of boundary layer characteristics on cavitation and the effect of unsteady cavitation on noise have been widely observed experimentally. In order to better understand these effects, an experiment with a two-dimensional hydrofoil, under sinusoidal pitching oscillation, was conducted in the 36-inch water tunnel. Three pin-hole-type pressure transducers were installed on the foil surface to measure pressure fluctuations and a hydrophone was used to measure the radiated cavitation noise. Two subjects are discussed in this paper: relationship of boundary layer transition and pressure fluctuations with the hydrofoil in oscillation, and noise generated by unsteady cavitation. The magnitudes of pressure fluctuations in transition and turbulent regions are found to be independent of oscillation amplitude and frequency. However, the development of boundary layer and occurrence of transition are delayed with an increase in oscillation frequency. The influence of hydrofoil oscillation on cavitation inception is also discussed. With the occurrence of leading edge sheet cavitation, a significant effect of foil oscillation on cavitation noise is measured. At high reduced frequencies, extensive cloud cavitation is formed during the final phase of sheet cavity collapse and the noise level is significantly increased. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1981
- Accession Number
- ADA098550
Entities
People
- Frank B. Peterson
- Young T. Shen