Modeling of Surfzone Bubbles Using a Multiphase VOF Model

We formulate a general multiphase model representing water-bubble mixture fluid and multi-component bubble populations. An enhanced 2-DV VOF model with a k− turbulence closure is used to model the mixture fluid phase. The bubble phase is governed by the advection-diffusion equations of the gas molar concentration and bubble intensity for groups of bubbles with different sizes. The initial bubble entrainment is formulated by connecting the flow shear stress at water-air interface and the bubble number intensity with a certain bubble size spectra as observed by Deane and Stokes (2002). The model is calibrated using the void fraction data measured in a plunging jet experiment (Hoque, 2002). The calibrated model is used to simulate regular wave transformation, breaking, and bubble generation and evolution processes over a barred bathymetry in the Long Wave Flume at Oregon State University. Model results are compared to measured data including both in-situ wave gages and video remote sensing.