Investigation of shock wave loading characteristics in single/dual cavitation bubble collapse near rigid walls

The shock wave effects resulting from bubble collapse have significant implications in hydraulic machinery, materials engineering, and biomedical fields. This study integrates experimental analysis, numerical simulations, and theoretical modeling to investigate the generation, propagation, and impact characteristics of shock waves from single and dual bubbles against rigid surfaces. The results indicate that within the range 1 ≤ γ ≤ 5.5, the peak shock wave pressure at wall monitoring points exhibits periodic fluctuations with γ, reaching a maximum at γ = 1.4, However, the highest pressure at any wall point is observed at γ = 1 and decreases as γ increases beyond 1.4. Wall damage is primarily governed by the initial pressure pulse of the shock wave, whereas the jet effects become more pronounced in the later stages of bubble collapse. Furthermore, within the range 1.3 ≤ γ ≤ 2.6, energy loss due to shock wave dissipation accounts for up to 85%. By introducing the spatial characteristic parameter ζ, this study further investigates the multi-scale coupling mechanisms of shock waves in dual-bubble collapse. The peak pressure is maximized at ζ = 3.7 (ω ≤ 4, γ ≥ 1), indicating that optimizing the ω-γ combination can mitigate cavitation damage, while adjusting θ allows for targeted energy focusing. These findings offer critical theoretical insights into shock wave prediction and the protective design of cavitation-prone material surfaces.