Two-phase Approach for Simulating Surfzone Bubbles

Wave breaking in the surfzone entrains large volumes of air bubbles into the water column, which strongly influences the optical and acoustical properties of the water, and subsequently makes optically-based observations difficult. In this presentation, we discuss a full two-phase model to study the evolution and transport of a bubble size distribution in a three-dimensional, turbulent flow. The model employs a VOF method to track the free surface. k-epsilon or LES models are used to describe turbulent closures. For validation, the model is used to simulate a pseudo-two-dimensional gas-liquid flow in a bubble column. The results show that, when the drag, lift and virtual mass forces are all included, the oscillation behavior and flow structures that were observed in the experiment can be captured.