FINITE-ELEMENT MODELING OF SURFACE-TENSION EFFECTS USING A LAGRANGIAN-EULERIAN KINEMATIC DESCRIPTION

An algorithm has been devised to model surface tension forces during f luid motion. It makes use of an Eulerian formulation applied to the go verning equations, and a Lagrangian treatment of the free surface. It is assumed that the effect of air on the free surface movement is negl igible, thus only the fluid domain is considered during the analysis. The free surface is subjected to a surface tension force proportional to the local curvature. This manifests itself as a simple and accurate method of modelling surface tension effects by virtue of the free sur face being explicitly determined. The method is validated by modelling the effect of surface tension on a static rod. A further numerical ex ample is used to illustrate the effect of surface tension on a non-equ ilibrium square rod. Wall adhesion modelling is demonstrated by modell ing the wetting of a capillary tube. Finally, the method is used in an industrial context to model the filling of mould cavities for which s urface tension forces are important.