Early Stage Cavitation in an Electrohydrodynamic Model

Cavitation, i.e., the formation of vapor bubbles in liquids under reduced pressure, is one of the most fundamental problems in fluid mechanics and plays a crucial role in a broad range of engineering applications. Despite significant prior investigations, inconsistencies in experimentally observed cavitation thresholds suggest limitations in existing theoretical models. Recent research in electrohydrodynamics (EHD) suggests that nanosecond-pulsed electric fields can induce localized pressure reductions via electrostriction, thus initiating cavitation at the nanosecond timescale in dielectric liquids such as water. This study investigates cavitation development using a time-dependent EHD model that couples electrostatic, mechanical, and phase field phenomena. Since the focus is on the very early stage of cavitation, the treatment of cavitation zone is based on two quasi-continuum approaches. By simulating the evolution of vapor mass fraction and comparing results with the Volume of Fluid (VOF) method, we develop a refined predictive framework that aligns with experimental observations. The model offers insight into the role of the waveform characteristics of the pulsed electric fields and various physicochemical parameters of water in the dynamics of early-stage cavitation, contributing to a deepened understanding of cavitation phenomena and laying the foundation for the development of EHD-based technologies for precision generation and control of cavitation in applications.