Experimental investigation of shock wave and microjet effects on wall pressure induced by two cavitation bubbles.

Cavitation has been a subject of scientific interest since Euler first discussed it in 1754 within his turbomachinery theory. The fascination intensified in the early 1900s when researchers observed that cavitation, which involves the formation of bubbles in a liquid under pressures below the saturated vapor pressure, significantly impacts performance in hydrodynamic systems like marine propellers and pumps, primarily through material erosion. The collapse of these bubbles generates shock waves and microjets, leading to ongoing debates about which phenomenon is more damaging. Our research has established that shock waves are the primary mechanism of damage in hydrodynamic systems with rigid boundaries. This conclusion is based on a precise correlation between the pressure produced and the timing of the shock impact from a single bubble collapsing near a rigid wall. To our knowledge, this precise experimental demonstration of shock impact timing has not been achieved before. Since bubbles usually appear in clusters within hydrodynamic systems, understanding their interactions is crucial. We are currently investigating the dynamics of two bubbles by varying their separation distance and size, and visualizing the resulting shock waves, and microjets. This research aims to elucidate how the presence of another bubble affects dynamics and pressure on nearby rigid walls, thereby enhancing our understanding of cavitation erosion mechanisms.