Accession Number : AD0286328

Title :   VENTILATED CAVITIES ON SUBMERGED THREE-DIMENSIONAL HYDROFOILS

Corporate Author : MINNESOTA UNIV MINNEAPOLIS ST ANTHONY FALLS HYDRAULIC LAB

Personal Author(s) : SCHIEBE,F.R. ; WETZEL,J.M.

Report Date : DEC 1961

Pagination or Media Count : 1

Abstract : Experimental studies were made to determine the air-entrainment rates of ventilated cavities for hydrofoils of finite span submerged below a free surface. The study was divided naturally into two parts; reentrant-jet cavities and pulsating or trailing-vortex cavities. A correlation parameter was derived to permit determination of the air-entrainment rates for cavities in the reentrant-jet regime assuming that all the air is lost from the cavity through the reentrant jet. As air was also lost through the tip vortices, some dependence was noted with aspect ratio. Air entrainment was a function of velocity for a given cavitation number and ambient pressure. Cavity instability or pulsation was observed at high air-injection rates for thin cavities. Trailing vortices were observed for thick cavities at the higher injection rates. The frequency of the plsations tended to increase as the foil approached the free surface. Measurements of lift and drag forces indicated little effect of the free surface for submergence ratios of 1 to 3 chords. (Author)

Descriptors :   *CAVITATION, *DRAG, *HYDROFOILS, *LIFT, *VORTICES, HYDRODYNAMICS

Distribution Statement : APPROVED FOR PUBLIC RELEASE