Accession Number : ADA325871

Title :   Numerical Simulation of Cavitating and Non-cavitating Flows over a Hydrofoil,

Corporate Author : MINNESOTA UNIV MINNEAPOLIS ST ANTHONY FALLS HYDRAULIC LAB

Personal Author(s) : Song, Charles C. ; He, Jianming ; Zhou, Fayi ; Wang, Ge

PDF Url : ADA325871

Report Date : APR 1997

Pagination or Media Count : 83

Abstract : The compressible hydrodynamic approach previously developed for small Mach number non-cavitating flows has been extended to simulate cavitating flows as well as non-cavitating flows. The extension is made possible by assuming a complex equation of state relating density and pressure to cover the liquid phase and the gas phase. Thus, the cavitation phenomenon is regarded as a single-phase flow phenomenon enabling the elimination of the cavity closure condition. The numerical model is an unsteady 3-dimensional flow model based on a large eddy simulation approach. It is applied to typical thin hydrofoils and thick hydrofoils at non-cavitating conditions and various cavitating flow conditions, including moving cavity, stable sheet cavity and sheet cavity/cloud cavity cyclical flow conditions. Computations are carried out primarily for 2-dimensional foils, but 3-dimensional flow characteristics are also examined. The computational results are compared with some available data; good quantitative and qualitative agreements are indicated. It is considered very significant that the sheet cavitation/cloud cavitation phenomenon is found to be similar to the viscous boundary layer flow separation/vortex shedding and washout phenomenon in many respects. Cavitation is found to trigger boundary layer separation in otherwise non-separated flow.

Descriptors :   *COMPRESSIBLE FLOW, *THREE DIMENSIONAL FLOW, *CAVITATION, *HYDROFOILS, COMPUTERIZED SIMULATION, EDDIES(FLUID MECHANICS), COMPUTATIONAL FLUID DYNAMICS, ANGLE OF ATTACK, VORTEX SHEDDING, VAPOR PHASES, FLOW FIELDS, LIQUID PHASES, UNSTEADY FLOW, FLOW SEPARATION, HYDRODYNAMICS, PRESSURE DISTRIBUTION, EQUATIONS OF STATE, BOUNDARY LAYER FLOW.

Subject Categories : Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE