ADVECTION OF AXISYMMETRICAL INTERFACES BY THE VOLUME-OF-FLUID METHOD

A criterion is proposed for the advection of axisymmetric interfaces. The location of an interface is followed by a volume-tracking techniqu e wherein a volume fraction parameter is assigned to each of the cells in a Eulerian grid system. The interface is discretized into a set of line segments fitted at the boundary of every pair of neighbouring co mputational cells. The orientation of a line segment is obtained by in specting the volume fractions of two neighbouring cells. The volume fr actions are then advected using the velocity components at the boundar y of the two cells. The following advection criterion is proposed: for advection in the axial direction the axial velocity u is assumed cons tant in the vicinity of each cell face; for advection in the radial di rection the radial velocity v times the radial distance r is assumed c onstant in the vicinity of each cell face, i.e. r(beta)v = const., whe re beta = 0 for Cartesian and beta = 1 for axisymmetric systems. The a bove criterion is used to develop an algorithm for the advection of ax isymmetric interfaces which is referred to as the 'axisymmetric flux l ine segment model for advection and interface reconstruction' or A-FLA IR.