A multigrid accelerated time-accurate inviscid compressible fluid flow solution algorithm employing mesh movement and local remeshing

An implicit scheme for the time accurate solution of three dimensional compressible fluid flow problems with moving boundaries on unstructured tetrahedral meshes is described. The numerical scheme is nominally second order accurate in both space and time and satisfies a geometric conservation law. For improved computational performance, the implicit equation system is solved by explicit iteration with multigrid acceleration. For the multigrid implementation, the coarse meshes are automatically generated by an agglomeration technique. The change in the solution domain geometry with time is handled by moving the mesh using a spring analogy scheme, with local remeshing performed in regions of reduced mesh quality.