Accession Number : AD0614837

Title :   THREE-DIMENSIONAL FREE-SURFACE EFFECTS ON HYDROFOILS,

Corporate Author : ENGINEERING RESEARCH ASSOCIATES TORONTO (ONTARIO)

Personal Author(s) : Richardson,J. R.

Report Date : MAR 1965

Pagination or Media Count : 51

Abstract : The report presents the first stage in the development of a three-dimensional theory for thin hydrofoils. The manner in which a foil can be built-up of doublets (representing thickness) and horseshoe vortices (representing lift) is described. The first step must therefore be to find the effect of the free-surface on the flow caused by doublets and vortices. The problem was not approached directly due to difficulties with the boundary conditions for moving disturbances. Instead, an analysis was made of a stationary source with oscillating strength. The results for pulse and step sources are then obtained from the oscillating case by Fourier transforms. Finally the pulse and step sources are integrated along the path of motion to obtain the required moving disturbances. The boundary conditions at great distances from the disturbance are automatically satisfied when this process is used. Equations are presented for the effect of the free-surface (at any Froude number) on the supervelocities caused by a moving doublet and horseshoe vortices oriented in vertical and lateral planes. The form of these equations was arranged so that computation is as easy as possible. (Author)

Descriptors :   (*HYDROFOILS, THEORY), VORTICES, HYDRODYNAMICS, CAVITATION, THICKNESS, SURFACES, LIFT, THREE DIMENSIONAL FLOW, TRANSFORMATIONS (MATHEMATICS), MOTION, NUMERICAL INTEGRATION, CANADA

Distribution Statement : APPROVED FOR PUBLIC RELEASE