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Center for Nonlinear Studies |
The standard Youngs interface-reconstruction method employs planar facets to represent interface geometry, therefore discontinuity between facets are unavoidable on cell faces for curved geometries. Also it is well known that Youngs method has difficulty dealing with T-intersections, probably because volume fractions carry insufficient information. Furthermore, Youngs method on structured meshes relies heavily on mesh regularity to utilize orthogonality of cell faces and convexity of cells. On arbitrary meshes, the loss of mesh regularity prevents the operations of Youngs method to be performed effectively. Effective algorithms are proposed for interface reconstruction with a volume of fluids method on an arbitrary mesh. The intersection of interface and cells are determined by a simple rule to walk on cell faces. The curvature of interface is derived with a least-squared method that naturally conserves partial volume. With the curved facets, the discontinuity of interface on cell walls is efficiently reduced. With an interface remapping/volume matching advection scheme (a predictor-corrector scheme), interfaces can be carried over time steps and the topology information is preserved. This purely geometrical interface reconstruction method is one order more accurate than Youngs method. Hydro advection tests show the new method is capable to represent interface geometry accurately. The new method has the ability to track corners, and the potential to deal with changes of interface topology.