Simulation of two‐phase flow with sub‐scale droplet and bubble effects

We present a new Eulerian‐Lagrangian method for physics‐based simulation of fluid flow, which includes automatic generation of sub‐scale spray and bubbles. The Marker Level Set method is used to provide a simple geometric criterion for free marker generation. A filtering method, inspired from Weber number thresholding, further controls the free marker generation (in a physics‐based manner). Two separate models are used, one for sub‐scale droplets, the other for sub‐scale bubbles. Droplets are evolved in a Newtonian manner, using a density‐extension drag force field, while bubbles are evolved using a model based on Stokes' Law. We show that our model for sub‐scale droplet and bubble dynamics is simple to couple with a full (macro‐scale) Navier‐Stokes two‐phase flow model and is quite powerful in its applications. Our animations include coarse grained multiphase features interacting with fine scale multiphase features.