A LES-based Eulerian-Lagrangian approach to predict the dynamics of bubble plumes

- A new Lagrangian Particle Tracking algorithm for LES of bubble plumes is presented.
- Delta functions are applied for the first time to the knowledge of the authors to this kind of problem.
- A new mapping approach based on the use of the bubble to mesh size ratio is suggested.
- We successfully validate the time-averaged velocities and second-order turbulence statistics.
- Slip velocity, interfacial forces and confinement effect are also analysed.

An approach for Eulerian-Lagrangian large-eddy simulation of bubble plume dynamics is presented and its performance evaluated. The main numerical novelties consist in defining the gas-liquid coupling based on the bubble size to mesh resolution ratio (Dp/Δx) and the interpolation between Eulerian and Lagrangian frameworks through the use of delta functions. The model's performance is thoroughly validated for a bubble plume in a cubic tank in initially quiescent water using experimental data obtained from high-resolution ADV and PIV measurements. The predicted time-averaged velocities and second-order statistics show good agreement with the measurements, including the reproduction of the anisotropic nature of the plume's turbulence. Further, the predicted Eulerian and Lagrangian velocity fields, second-order turbulence statistics and interfacial gas-liquid forces are quantified and discussed as well as the visualization of the time-averaged primary and secondary flow structure in the tank.