Vapor and gas bubble growth with phase transition near a wall*

Bubbles cavitate near hard surfaces during biomedical therapies, such as ultrasound-focused breakup of urinary stones. The bubbles oscillate during the treatment due to the compressive and tensile ultrasound pressures. During the oscillations, the liquid evaporates into the gas bubble, water vapor condenses, and non-condensable gases dissolve into the liquid. These dynamics have been studied in 1D spherical symmetric numerical simulations. We conduct simulations of asymmetric bubble dynamics near a rigid wall with three phases (liquid, vapor, and gas) using the open-source Multi-component Flow Code [Bryngelson et al. Comp. Phys. Comm. (2020)]. MFC solves the 3D, compressible Navier-Stokes equations using a six-equation multiphase numerical model including phase change. We verify the solver using 1D shock tube and 2D underwater explosion simulations. We observe condensation at the bubble interface during ultrasound-induced vapor-gas oscillations. Results varying driving pressure, frequency, and bubble stand-off distances will also be presented.