Numerical and Experimental Investigation of the Dynamics of a Single Bubble Adjacent to a Flat Plate and a Cylindrical Rod with Varying Radii

Abstract

In this work, we investigated the dynamics of a single cavitation bubble near a solid cylindrical rod with five different radii and a cylindrical rod with infinite radius (called here as flat plate) at different relative wall distances. First, we simulated dynamics of the cavitation bubble near a flat plate using a fully compressible model and validated the results with our experimental data. Second, we analyzed the effects of three relative wall distances (different _\(\gamma\)RB the effects of different radii (different _\(\gamma\)CR) of cylindrical rod on the bubble dynamics. Finally, we compared the bubble dynamics near a cylindrical rod and the flat plate at different relative wall distances and under effects of various radii of cylindrical rod. The results showed that the continuous enhancement of the cylindrical rod’s radius can affect the bubble collapse dynamics. In addition, the value of the wall pressure at the flat plate condition was about 1.9 MPa which is slightly lower than the value of the impact pressure at the condition of _\(\gamma\)CR = 8:0 with the value of 2.1 MPa. Through the comparison of the jet velocity evolution at different conditions of  _\(\gamma\)CR , it was found that the jet velocity at the conditions _\(\gamma\)CR = 0:5 and _\(\gamma\)CR = 1:0 can be reached it’s highest value at both relative wall distances of _\(\gamma\)RB = 0:6 and _\(\gamma\)RB = 0:9. Furthermore, a similar evolution process of the jet velocity was obtained for the conditions _\(\gamma\)CR = 4:0; 6:0; 8:0 at both relative wall distances of _\(\gamma\)RB 0:6 and _\(\gamma\)RB = 0:9 compared to the flat plate condition. For a radius of cylindrical rods six times larger than bubble maximum radius, similar collapse dynamics for the rod and flat plate were observed.