Numerical simulation of transient pressure characteristics of arc discharge in water

The high-voltage pulse discharge technology in water has good repeatability, energy controllability and safety. It proves to be capable of generating strong sound sources, serving as a means of counteraction for underwater attack and defense. During the pulse discharge, the rapid expansion of the plasma channel generates intense optical and thermal radiation, which promotes the rapid expansion of the gas-liquid interface, forming cavitation bubbles and releasing pressure waves (shock waves, secondary pressure waves, etc.) outward. Due to the incomplete systematic study of the correlation between bubble motion and pressure wave propagation. Given this, this paper is based on the principle of explosion equivalence, the plasma channel is regarded as the underwater equivalent explosion source. Subsequently, the underwater detonation is simulated by Smoothed Particle Hydrodynamics (SPH), the aqueous medium employs the Mie-Gruneson state equation, while the plasma channel adopts the JWL state equation, and the SPH integral approximation method and the particle approximation method are used to discretize the underwater explosion control equation. In the simulation process, aiming to solve the problem of accuracy decline caused by the drastic change of particle volume in the flow field, the adaptive particle splitting and merging algorithms are applied. Ultimately, employing the SPH method enables accurate simulation of the complex processes, including the expansion, contraction, and collapse of bubbles, and facilitates the analysis of the spatial distribution characteristics and propagation laws of the whole process of shock wave.