서강대학교

초록/요약

Numerical simulation is performed for bubble collapse under a pressure pulsing condition, acoustic droplet vaporization of a volatile droplet near a wall and inside a circular tube. For the computations of bubble collapse under a pressure pulsing condition, bubble motion is investigated by using a level-set method which is combined with the ghost fluid method and the semi-implicit pressure correction method to include the effect of compressibility of liquid and gas. The effects of surface tension and viscosity, magnitude of pressure pulse, initial bubble location and presence of wall are investigated. For the computation of acoustic droplet vaporization of volatile droplet near a wall and inside a circular tube, the level-set functions are introduced to track the droplet and bubble surfaces, respectively. The level-set method is combined with the ghost-fluid and semi-implicit correction method to implement the effects of liquid-vapor phase change and bubble compressibility. The effects of initial droplet location and size, acoustic conditions, surface tension, tube radius and inflow velocity on bubble growth and wall shear stress are quantified.