Developing spline based overset grid assembling approach and application to unsteady flow around a moving body

Overset or Chimera grid approach is one of methods to cope with complex geometries. A spline based overset grid assembling system has been developed. The sys- tem is based on structured grid approach and covers comprehensive features for overset assembling, i.e., grid generation, grid modification, and computing Receptor-Donor Con- nectivity (RDC) for overset interpolation. Ferguson spline curve is used to compute curves through grid points and cell centers for trimming grids and computing RDC robustly and accurately. Flow simulation around Kriso Container Ship(KCS) with jointed grids shows good continuity of flow field between the grids. The overset grid assembling is enhanced to unsteady problem as dynamic overset approach coupled with a solver which also has been developed in National Maritime Research Institute, Japan. Computed results for pitchup spheroid are compared with measured data and show good agreement in unsteady force acting on the spheroid. It is confirmed that the system has capability to simulate flow field around jointed grids and unsteady flow with dynamic overset assembling approach practically