Intergrid-boundary definition method for overset unstructured grid approach

The use of the overset concept for the unstructured grid method is relative ly unexplored. However, the overset approach can extend the applicability o f the unstructured grid method for real engineering problems without much n eed for code development. The multiple moving-body problem is one of those applications. Improvement in local resolution for Euler/Navier-Stokes compu tations on unstructured grids is another use of the overset concept. An eff icient and robust algorithm to localize the intergrid boundaries for the ov erset unstructured grid method is proposed. Simplicity and automation in th e intergrid-boundary definition are realized using the wall distance as a b asic parameter. The neighbor-to-neighbor jump search algorithm is efficient ly utilized in the method. The robustness and efficiency of the search is i mproved by the use of subsidiary grids that are generated as a byproduct of the Delaunay triangulation method. The basic procedure of the present meth od is described for a multielement airfoil problem. The effects of the over set method on the solution accuracy and the convergence are tested by ONERA M6-wing. The capability of the method is demonstrated by application to an airplane-rocket boaster separation problem.