A HEIGHT FLUX METHOD FOR SIMULATING FREE-SURFACE FLOWS AND INTERFACES

A new technique for the numerical simulation of the free surface flows is developed. This technique is based on the finite element method wi th penalty formulation, and a flux method for surface advection. The a dvection part which is completely independent of the momentum solver i s based on subdividing the fluid domain into small subvolumes along on e of the co-ordinate axis. The subvolumes are then used to find the he ight function which will later describe the free surface. The free sur face of the fluid in each subvolume is approximated by a line segment and its slope is calculated using the volume of the fluid in the two n eighbouring subvolumes. Later, the unidirectional volume flux from one subvolume to its neighbouring one is calculated using the conservatio n laws, and the new surface line segments are reconstructed. This tech nique, referred to as the Height-Flux Method (HFM) is implemented to s imulate the temporal instability of a capillary jet. The results of th e numerical simulation well predict the experimental data. It is also shown that the HFM is computationally more efficient than the techniqu es which use a kinematic boundary condition for the surface advection.