A Parallel dynamic overset grid framework for CFD applications*

The overset grid technique enables the flow solvers to handle complex geometries that can’t be represented well using a single grid, or unsteady moving grid simulations without dealing with remeshing. A new scalable parallel grid assembly and interpolation framework is developed and integrated with a sharp interface curvilinear immersed boundary (CURVIB) flow solver to handle multiple overlapping domains and structures in the fluid domain. In order to achieve a good parallel scalability several steps are implemented in our framework: 1) Oriented bounding boxes (OBB) are constructed instead of axis-aligned bounding boxes; 2) Gradient search for identifying the donor; 3) Removing the I/O file for communication with flow solver; 4) Efficient vectorized implementation for velocity interpolation; and 5) Using general non-inertial frame of reference to prevent the recomputation of curvilinear grid metrics. This framework is validated against several test cases to insure the accuracy of the solvers. Our results show a good scalability and accuracy for this new framework.