COMS (Conservative Overset Mesh Solver) is a conservative overset mesh solver. Overset mesh technique is useful in problems involving multiple relatively moving components. With overset mesh technique each component is meshed independently. Since there is no face-to-face connectivity between overset meshes, flux cannot flow through cell-faces across component meshes. This causes non-conservation of flux in mesh-system. COMS physically connects each component mesh by remeshing inter-grid regions with Advancing Front Delaunay algorithm. This way total flux in mesh-system is conserved.

COMS solves the two-dimensional Euler equations on unstructured grid topology. Tailor which is a three-dimensional and load-balancing overset mesh solver is an improved version of COMS however, Tailor does not remesh component meshes into a single grid, therefore, is not flux-conservative.

Below is an example shows a background and an overset mesh. Some of the cells in the overlapping region are removed and remeshed to connect the meshes.

The following figure shows application of COMS to oscillating airfoil test case. At each time step, COMS remeshes the inter-grid region.