Experimental and numerical study on triple underwater explosion bubble's interaction with different array distances and phases

A series of experiments and simulations are performed to study the interaction of three underwater explosion bubbles of approximately equal size for different distance and phase combination. Small-scale underwater explosion experiments are conducted in a water tank, and the behaviors of three bubbles with different distance were captured using high-speed photography, and based on which, numerical models with different phase and distance combinations are established to analyze the pulsation and water jets phenomenon. The results indicate that while three bubbles are generated at the same time, three water jets pointing to the center of the circle are produced, and the bubble pulsation period decreases with the increase in the distance, and when the dimensionless distance is greater than 3, the dimensionless period reaches 1.0, which indicating negligible interaction between three bubbles. While three bubbles are generated with different phases, the direction of the water jets changes to diverging from the center of the circle, and with the increase in the asynchronous phase difference, the jet velocity increases, and the angle between the velocity vectors gradually decreases. The interaction phenomena of three bubbles generated with different initial distances and phase differences are divided into five categories by the water jet velocity, namely, coalescence, failed catapult, piercing jet, protrusion jet, and jet toward.