Interface Tracking With a Coupled Level Set /VOF/Ghost Fluid Method: Application to Jet Atomization

We are here concerned by the primary break-up of a jet: a lot of topological changes occur and the Level Set Method thus appears well designed for our purpose. To describe the interface discontinuities, we use the Ghost Fluid Method (GFM) and a projection method is used to solve incompressible Navier-Stokes equations that are coupled to a transport equation for the level set function. The main drawback of level set methods is that numerical computations in the re-distancing algorithm can generate mass loss in under-resolved regions. To improve mass conservation extension of the method can be developed, namely a coupling between VOF and Level Set. In order to illustrate the abilities of the Level Set/VOF/Ghost Fluid method for interface tracking, we present a 3D simulation of the primary atomization zone of a turbulent liquid jet. The turbulence initiates some perturbations on the liquid surface, that are enhanced by the mean shear and break-up occurs. The generated liquid parcels show a wide range of shapes. Particular behaviors such ligament detachments, droplet formations and break up are described.