Instability of Partial Cavitation: A Numerical/Experimental Approach

Abstract

Sheet cavitation and the transition to cloud cavitation on hydrofoils and marine propellers results in a highly unstable flow that can induce significant fluctuations in lift, thrust and torque. In order to gain a better understanding of the complex physics involved, an integrated numerical/experimental investigation was carried out. A 2D NACA 0015 hydrofoil was selected for study, because of its previous use by several investigators around the world. The simulation methodology is based on large eddy simulation (LES), using a barotropic phase model to couple the continuity and momentum equations. The complementary experiments were carried at two different scales in two different water tunnels. Tests at the Saint Anthony Falls Laboratory (SAFL) were carried out in a 19 cm square water tunnel and a geometrically scaled up series of tests were carried out in the 30 cm square water tunnel at the Versuchsanstalt fur Wasserbau (VAO) in Obernach, Germany. The tests were designed to complement each other and to capitalize on the special features of each facility.