The Stability of An Air-Maintained Cavity Behind A Stationary Object In Flowing Water.
Abstract
Studies of a projectile in an air-maintained cavity were made with supported flat disks in a free-surface water tunnel. Air was injected immediately behind the jet. Curves of entrainment-rate coefficient vs. cavitation number were plotted for a 1-in. disk at 3 stream velocities; each curve shows a minimum. The point of minimum entrainment coincided with a transition from a double vortex to a re-entrant jet configuration. Explanations for the differing slopes on either side of the minimum are given. Using the maximum cavity diameter as a reference length for the Froude number a plot of the entrainment data was made which was independent of nose shape. The extreme slope of the curves at lower cavitation numbers may be due to a double-vortex mechanism which seems to effectively transmit the air downstream. A gravity effect becomes important at low cavitation numbers.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 05, 1951
- Accession Number
- AD0208556
Entities
People
- J. P. O'neill
- W. W. Swanson
Organizations
- California Institute of Technology