Extension of an immersed boundary method for large eddy simulation of turbulent flows

In this paper, an immersed boundary method is extended to large eddy simulation of turbulent flows. For the interior nodes in the immediate vicinity of the immersed wall, some of their neighbouring nodes are in the solid phase, and the flow variables at these interior nodes cannot be calculated by solving the governing equations. In the present immersed boundary method, the flow variables at these nodes are determined via an approximate form of solution involving the boundary condition. A wall model based on the simplified turbulent boundary layer equations is introduced to alleviate the requirement of mesh resolution in the near-wall region. The wall shear stress prescribed by the wall modelling technique and the no-penetration condition are enforced at the immersed boundary to evaluate the velocity at an interior node in the immediate vicinity of the wall. A dynamic subgrid-scale model is adopted in the framework of the immersed boundary approach. Several numerical experiments have been conducted to verify the ability of the present method. The predicted results agree well with the published experimental or numerical data.