Accession Number : AD0654145

Title :   AN EXPERIMENTAL STUDY OF THE HYDROELASTIC INSTABILITY OF SUPERCAVITATING HYDROFOILS.

Descriptive Note : Technical rept., no. 89, 1 Oct 64-30 Sep 66,

Corporate Author : MINNESOTA UNIV MINNEAPOLIS ST ANTHONY FALLS HYDRAULIC LAB

Personal Author(s) : Song,C. S. ; Almo,John

Report Date : FEB 1967

Pagination or Media Count : 55

Abstract : Some experimental findings concerning the flutter characteristics of two-dimensional supercavitating flat-plate hydrofoils are reported. The experiment was carried out in a free-jet water tunnel using wedge-shaped hydrofoils (practically rigid) elastically supported to permit two degree of freedom motions in translational and rotational modes. Critical flutter speed, flutter frequency, flutter amplitude ratio, and damping factor were measured for various elastic and flow conditions. The measured stability boundary curves agree, qualitatively, with an existing linear theory. The effect of leading-edge condition, free surface, ventilation, cavity length, and friction were also explored. The magnitude and the complexity of the leading-edge effect on the critical flutter speed is particularly noteworthy. A cavity pinch-off phenomenon was revealed. Also revealed are the occurrence of a rolling mode of flutter and cavity pulsation which may coexist with the two degree of freedom flutter under certain circumstances. (Author)

Descriptors :   (*HYDROFOILS, *FLUTTER), STABILITY, ELASTIC PROPERTIES, FLUID DYNAMICS, CAVITATION, VELOCITY, DAMPING, WEDGES, LEADING EDGES, FRICTION

Subject Categories : Marine Engineering

Distribution Statement : APPROVED FOR PUBLIC RELEASE