Numerical Investigation of Free Surface Effect on Cavitation

摘要

Numerical simulation is done for the investigation of the free surfacerneffect on the cavity shape of a hydrofoil in shallow water. The airvapor-rnwater three phases flow around the hydrofoil is resolved usingrnthe scale adaptive simulation (SAS) method. The two interfaces, i.e. thernair-water free surface and the vapor-water cavitation interface, arerntracked simultaneously by the volume of fraction (VOF) method, withrnthe cavity shape modeled by the Schnerr-Sauer's cavitation model. Onerntwo dimensional validation case for the hydrofoil with thicknessrnD=16mm in a tunnel is presented, and then the validated method isrnused to simulate the cavitation flows around the same hydrofoilrnoriented with several attack angles (Ak = 2̊, 5̊ and 8̊) under variousrnwater depths (H=0.07m, 0.10m and 0.13m). The foil’s drag coefficients,rntotal vapor volumes and the cavity shapes of these free surface casesrnare compared and analyzed.