(30c) Investigations on the Mass Diffusion Across Interfaces of Oscillating Bubbles

The mass diffusion across interfaces of oscillating bubbles is a complex phenomenon, leading to great difficulties for the numerical investigation. During nonlinear oscillations of bubbles, the position of the interface moves rapidly. Hence, the concentration of the gas (or vapor) in the bubble varies significantly. The fast moving interface also generates a strong velocity field, which prominently affects the local mass diffusion process. If the bubble contains more than one species (e.g. a mixture bubble with both gas and vapor or bubbles with different types of gases), there will be more paramount influencing factors involved. In the present paper, a new numerical approach is developed to simulate the mass diffusion problem. In our model, liquid compressibility, surface tension and nonlinearity are all included. Plus, we further considered the complexity caused by the mixture bubbles with both gas and vapor inside. The results are demonstrated in terms of the threshold of the diffusion (corresponding to the zero flux rate) and diffusion rate for a given set of parameters. The potential application of the main findings are also explained with the background of industrial cases.