Implementation and Testing of Overset Grid Capability for Supersonic Flows

The paper discusses the overset grid methodology implementation and its testing at transonic and super-sonic Mach numbers. The motivation is to make the grid generation process easier and less time consuming, without hampering the accuracy of simulation. In the near-body region body fitted curvilinear structured grids and in the off-body region Cartesian grids were used, which gives large scope for automation in the off-body grid generation. Donor cells for fringe cells have been searched by using the Barycentric coordinates. The interpolation of conservative variables from donor cells to fringe cells has been carried out through area weighted averaging. It is observed that this interpolation technique is preserving the conservation at the discontinuities like shocks, without causing any spurious oscillations. Efficient polygon clipping algorithm has been used for calculating the various area fractions. The module was tested for steady state Euler & viscous flows and unsteady state moving shock problems. In all the cases shocks crossed the overset boundary without any distortion