An Improved Tri-linear Interpolation Method for Hybrid Overset Grids and Its Application

Abstract

Tri-linear interpolation method is the most popular approach in data transferring between overset grids due to its briefness and robustness, however it is not sufficient to guarantee the conservation of flow variable. An improved tri-linear interpolation method for overset mesh is presented. A cell-cut algorithm is applied to construct a local supermesh in the overlapping grid area, which could be used to improve the conservation of flow variable. The number of donor cells is expanded reasonably to improve the accuracy of interpolation, and a volume weighted method is applied to eliminate interpolation error coming from the grids mismatch in the overlapping grid areas. Numerical results show that compared with original tri-linear interpolation method, the improved method could reduce the numerical errors, interpolate the flow variables more accurately. For linearly and non-linearly distributed flow variables, the improved tri-linear method is more conservative because it has inherited the conservation of supermesh, and it is robust and engineering-practical for complex engineering applications.