Viscoelastic Effect on the Wall Pressure Induced by Tandem Cavitation Bubbles near a Rigid Boundary: A Numerical Study

High-speed liquid jet and pressure waves are key features in near wall collapse of cavitation bubbles, which generates strong hydrodynamic loadings on solid surface. However, previous studies mainly focus on cavitation bubbles in Newtonian fluid, while the viscoelastic effect of the liquid is not well understood. In this letter, we perform numerical studies on the violent collapse of cavitation in viscoelastic fluid near a solid boundary. Our simulation results reveal that at high Deborah number, the cavitation bubble dynamics are governed by both the inertia and fluid elasticity. In this regime, the bubble exhibits underdamped oscillations with high-frequency and produces a premature jet, resulting synergistic effect on the wall pressure between the pressure pulse from the wave and the jet impact. The reason is due to the frequent mutual conversion between the elastic potential energy of the fluid and the kinetic energy of the cavitation bubbles. Furthermore, we observe that the amplitude of the wall pressure induced by cavitation bubbles is reduced by over 90% when considering the viscoelastic effect, while the interaction between cavitation bubbles can increase the amplitude of the wall pressure by up to 3.6 fold.