The Front-Tracking ALE Method: Application to a Model of the Freezing of Cell Suspensions

A new front-tracking method to compute discontinuous solutions on unstructured finite element meshes is presented. Using an arbitrary Lagrangian–Eulerian formulation, the mesh is continuously adapted by moving the nearest nodes to the interface. Thus, the solution is completely sharp at the interface and no smearing takes place. The dynamic node adjustment is confined to global nodes near the front, rendering remeshing unnecessary. The method has been applied to the osmotic motion of a two-dimensional cell arising from a concentration gradient generated by a moving solidification front. The engulfment of one cell by an advancing solidification front, which rejects the solutes in a binary salt solution, is then computed. The results indicate that the ice increases the solute gradient around the cell. Furthermore, the presence of the cell, which prevents diffusion of the solute, leads to large changes in the morphology of the ice front.