21st Congress of International Council of the Aeronautical Sciences, Melbourne, Australia, 13-18 September, 1998
Paper ICAS-98-2.7.3

A MULTIGRID ALGORITHM FOR INVISCID FLOW COMPUTATIONS ON UNSTRUCTURED GRIDS

Berglind T., Tysell L.
The Aeronautical Research Institute, Sweden

Keywords: multigrid algorithm, inviscid flow computations, unstructured grids

This work demonstrates the efficiency of multigrid convergence acceleration technique for an overset grid method. The flow solver scheme is based on an explicit, vertex-based, finite volume scheme with central difference type of spatial discretization. In contrast to muItigrid for structured grids, the grid quality inevitably degrades with the level of the coarse grids. The importance of robust coarse grid operators for multigrid algorithms on unstructured grids is discussed. A new coarse grid operator is proposed. The capabilities of the multigrid scheme are assessed by solving the flow equations over configurations of varying geometrical complexity. The convergence by multigrid alone is accelerated by an order of magnitude in both 2D and 3D.

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