Experimental study on the characteristics of microjets and shock waves of cavitation bubbles near elastic boundaries

Studying the characteristics of cavitation bubble microjets and shock waves is of great significance to reveal cavitation erosion mechanisms in hydraulic engineering. In this paper, a high-speed dynamic acquisition system and an electric pulse-induced cavitation bubble system are used to study the interaction between cavitation bubbles and different elastic boundaries from the perspective of microjets and shock waves. By analysing the difference in the microjet direction near different elastic materials, the relationship between the dimensionless critical distance of the microjet direction characteristics and the dimensionless elastic modulus of the boundary material is preliminarily established. Via quantitative analysis, the maximum velocity of the microjet near different elastic boundaries increases gradually and tends to stabilize with increasing dimensionless distance. Additionally, the shock wave intensity and propagation characteristics near different elastic boundaries are qualitatively analysed through images. The cavitation impact characteristics of the microjet and shock wave are compared. The elastic deformation characteristics of elastic materials under the penetration of microjets are the main influencing factors of cavitation erosion of elastic materials, while the effect of the shock wave on elastic materials is weak.