A FRACTIONAL STEP METHOD FOR UNSTEADY INCOMPRESSIBLE FLOWS ON UNSTRUCTURED MESHES

In this paper, an implicit fractional step method for the solution of the two-dimensional, time dependent, incompressible Navier-Stokes equa tions is presented. The current method was developed for use on an uns tructured grid made up of triangles. The basic principles of this meth od are that the evaluation of the time evolution is split into interme diate steps and that for the spatial discretization of the flow equati ons, a finite volume discretization for an unstructured triangular mes h is used. The current methodology, which has been tested extensively for steady problems, is now applied for the numerical simulation of un steady flows. Several cases were tested, such as plane or axisymmetric channels, a square cavity and an axisymmetric stenosis.