Level Set Simulation of Bubble Bursting Process

Bubble bursting occurring in the wave boundary layer can produce small droplets. These droplets increase the surface area of the ocean and thus enhance the air-sea exchange of momentum, heat, and moisture. This paper aims to utilize the level set method coupling with the Navier-Stokes solver to study the dynamics of single rising bubble and bubble bursting.

Single rising bubbles are first simulated to study bubble deformation over a wide range of Reynolds and Eotvos numbers. The shapes of bubble are in excellent agreement with those observed in experiment. The bubble bursting process is then investigated. When a rising bubble reaches the free surface, a water jet is formed and breaks into jet droplets. The level set method is able to capture this bursting process. The simulation results further reveal that under no wind condition, a strong air jet with a velocity of 10-18 m/s is formed together with the water jet. The bursting process under wind condition is also investigated. Unlike no wind condition, a half of the bubble is simulated because the process is no longer axisymmetric. The results show that the water jet curves toward the upwind direction due to pressure variation around the jet.