A fast and reliable overset unstructured grids approach

A cell-centred overset unstructured grids approach is developed. In this approach, the intergrid boundary is initially established based on the wall distance from the cell centre, and is then optimized. To accelerate the intergrid-boundary definition much more, a neighbor-to-neighbor donor search algorithm based on advancing-front method is modified with the help of minimum cuboid boxes. To simplify the communications between different grid cell types and to obtain second-order spatial accuracy, a new interpolation method is constructed based on linear reconstruction, which employs only one layer of fringe cells along the intergrid boundary. For unsteady flows with relative motion, the intergrid boundary can be redefined fast and automatically. Several numerical results show that the present dynamic overset unstructured grids approach is accurate and reliable.