Parametric Assessment of Size and Peak Pressure Variability for Cavitation Bubbles Induced by Low-Voltage Discharge

Abstract Cavitation presents a significant challenge in the operation and longevity of hydraulic machinery. Studying a single cavitation bubble can provide fundamental insights into the phenomenon. One simple and popular method to generate such bubbles is through a low-voltage discharge between two contacting electrodes to create a spark that locally vaporizes water. This study investigates the repeatability of low-voltage discharge in generating consistent bubbles. The electrode length is one parameter that influences the bubble size. However, the excess length (the electrode length after the contact point) is shown to be the primary variable influencing the bubble size rather than the total electrode length. Additionally, even for bubbles of similar size, significant variability in wall pressure peaks was observed for bubbles generated far from the surface. This variability correlates with the time the electrodes require to melt and break. Longer melting times are associated with extended bubble lifetimes and lower pressure peaks.