22nd Congress of International Council of the Aeronautical Sciences, Harrogate, UK, 28 August - 1st September, 2000
Paper ICAS 2000-2.6.3

OVERSET UNSTRUCTURED GRID METHOD FOR FLOW SIMULATIONS OF COMPLEX AND MULTIPLE BODY PROBLEMS

K. Nakahashi, F. Togashi
Tohoku University, Japan

Keywords: cfd, unstructured grid, overset grid

The use of the overset concept for the unstructured grid method is discussed for the numerical simulations of flows around complex and multiple bodies in relative motion. The intergrid boundaries in the overset grids are automatically localized using the wall distance as a basic parameter. The search for donor cells is efficiently performed by the neighbor-toneighbor jump search on a modified convex domain utilizing a byproduct of the Delaunay triangulation method. The capability of the method is demonstrated by simulations of a rocket-booster separation from a supersonic experimental airplane. A grid around the rocket booster is overset on the airplane grid that covers the entire flow field. The complicated configuration of the rocket booster is faithfully reproduced by a single grid. This capability of the unstructured grid significantly simplifies the overset procedure as compared with the conventional structured grids approach. Comparisons of the computed results with the experiment show good agreements in the lift and pitching moment histories.

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