Study on the collapse process of double cavitation bubble based on coarse-grained force field

Cavitation bubbles predominantly exist in clustered formations in nature, where complex inter-bubble interactions involving coupling and interference mechanisms govern their dynamic evolution. While significant progress has been made in understanding single cavitation bubble, research on multi-bubble interactions remains notably underexplored. To understand the characteristics of multi-cavitation bubble collapse and inter-bubble interaction, the paper studies the microscopic characteristics in the free domain based on the coarse-grained force field. It considers factors such as bubble radius, bubble distance, and whether the bubbles contain gas or not to reveal the morphology, local density distribution, and velocity distribution change of double bubbles. Results show that as the bubble radius increases, the local density changes are more prominent, and the collapse time and the depression depth increase. The jet is more likely to face the side of double bubbles facing each other during formation, and the jet deflection angle also gradually increases. As the bubble distance increases, the jet deflection angle decreases. The larger the initial radius of the gas-containing double bubble, the more dispersed the nitrogen is, and eventually small water-insoluble bubbles such as mushroom, umbrella, and curved moon are formed. What’s more, gas-containing double bubbles collapse at a slower rate than non-gas-containing double cavitation bubbles, and the gas attenuates the collapse effect.