High-Order Overset Flux Reconstruction Method for Dynamic Moving Grids

Overset meshes have a unique advantage in handling moving boundary problems as remeshing is often unnecessary. Recently, overset Cartesian and strand meshes were used successfully to compute complex flow over rotorcraft. Although it is quite straightforward to deploy a high-order finite difference method on the Cartesian mesh, the near-body solver for the strand mesh is often limited to second-order accuracy. In the present study, a high-order flux reconstruction solver, hpMusic, is developed on both the near-body and background grids, and it is extended to handle moving boundary problems. Accuracy studies are carried out, and the designed order of accuracy is obtained for both inviscid and viscous flows. The method is then tested for a benchmark dynamic airfoil problem from the 4th International Workshop on High-Order CFD Methods. Mesh and order-convergent results are obtained and compared with those from other groups. Finally flow over a hovering rotor is simulated to compare with experimental data. In this case, the present high-order solver is capable of generating and propagating tip vortices with high resolution. Good agreement is achieved with experimental data in tip vortex core size, location, and the swirl velocity at third-order accuracy.