Simulating Flow over Periodic Hills Using a Dual-Mesh Hybrid Solver with High-Order LES

In this work, we present a hybrid solver coupling a high-order LES solver with Cartesian mesh and a RANS solver with body-fitting mesh. This hybrid solver is developed within a dual-mesh consistent hybrid framework, where LES and RANS simulations for the same flow are conducted simultaneously on different computational domains and different meshes. In the LES, an immersed boundary method with relaxation forcing is used with the Cartesian mesh to enforce non-slip boundary conditions at the curved boundaries. The flow over periodic hills at Reynolds number Re = 2800 is simulated using the new solver. The adequacy of the boundary representation and forcing strategy is demonstrated. It is concluded that dual-mesh consistent hybrid framework is successful in the context of coupling a high-order LES solver on Cartesian mesh and a general-purpose RANS solver on body-fitting mesh. The approach explored in the new hybrid solver could be used to take advantage of the potential of many existing academic codes to simulate practical flows in industry and in nature, where complex geometries and wall boundaries currently represent major hurdles.