Abstract: Cavitation damage widely occurs in the flow passages of a hydraulic machine, and the right-angled wall is a common type of wall surfaces. However, understanding of dynamic behaviors of a cavitation bubble near a right-angled concave wall is very limited. This study is aimed to investigate the influence of a dimensionless distance parameter γ on the dynamic behaviors of a cavitation bubble in symmetrical position near a right-angled concave wall, focusing on the characteristics of the micro-jet and its influence on the wall. The results show two different types of micro-jets are generated during bubble collapsing, i.e., the main jet and the sideway jet. The main jet points to the intersection of the two perpendicular walls; the direction of the sideway jet varies with time, which may exert a force on the walls. Both jets impose an impact on wall pressure that is inversely related to the dimensionless distance parameter γ－a larger γ leads to a smaller impact on wall pressure. In the range of γ < 2.5, both jets produce considerable effect, but the main jet plays a dominant role in all the cases.

Key words: cavitation dynamics, characteristics of micro-jet, dimensionless distance parameter, right-angled concave wall, main jet, sideway jet