Author(s): Tong Qu; Jie Li; Zhuoqi Zhao; Jiayao Bao
Linked Author(s):
Keywords: Cavitation bubble low ambient pressure shock wave
Abstract: Due to the reduced atmospheric pressure at high altitudes, the dynamic characteristics of cavitation bubbles differ significantly from those at standard atmospheric pressure. In this study, the shock wave characteristics from cavitation bubble collapse near a rigid wall under low ambient pressure conditions (below standard atmospheric pressure) are investigated. It was found that when the bubble collapses near the rigid wall, the shape of the collapse shock wave changes from multi-layered to single-layered as the dimensionless bubble-wall distance (γ, γ = L1/Rmax, where L1 is the distance from the center of the cavitation bubble to the wall, and Rmax is the maximum radius of the cavitation bubble) increases. Within the ambient pressure range of 56 kPa to 96 kPa, there is a critical value, γc. The relationship between γc and ambient pressure PA follows the equation: γ_c=26.97P_A^ (-0.56). When γ > γc, the bubble collapse shock wave exhibits a single-layer, spherically symmetric shape. In contrast, when γ < γc, the shock wave becomes multi-layered and exhibits non-spherical symmetry. In addition, when the ambient pressure is constant, the peak pressure of the collapse shock wave decreases as γ increases. When γ is constant, the peak pressure decreases with a reduction in ambient pressure, and the proportion of shock wave energy in the total mechanical energy of the bubble follows a similar trend. These new findings hold important theoretical significance for understanding the damage effects of cavitation bubble collapse on rigid walls under low ambient pressure conditions.
Year: 2025