Research on the dynamics of a restricted cavitation bubble near a symmetric Joukowsky hydrofoil

Abstract

In the present paper, the restricted cavitation bubble dynamics near a symmetric Joukowsky hydrofoil are researched theoretically and experimentally. Using Kelvin impulse theory, the Joukowsky transformation, and the circle theorem, a theoretical model for restricted bubble dynamics is established to analyze the collapse jet characteristics. The validity of this model is then verified using high-speed photographic experiments. The velocity and direction of the collapse jet at specific position angles are quantitatively analyzed. Furthermore, the spatial characteristics of the Kelvin impulse direction near the symmetric Joukowsky hydrofoil are revealed by theoretical results. The main conclusions include the following: (1) the new theoretical model is proven to be effective in predicting the direction of the collapse jet for a restricted bubble near a symmetric Joukowsky hydrofoil. (2) As the distance between the bubble and hydrofoil increases, the collapse jet direction changes from pointing toward the nearest wall to pointing toward the center of the hydrofoil. (3) The variation rate of the Kelvin impulse direction for the restricted bubble is very sensitive to the bubble position near the two ends of the symmetric Joukowsky hydrofoil.