DIRECT NUMERICAL SIMULATION OF INTERACTIONS BETWEEN A MIXING LAYER AND A WAKE AROUND A CYLINDER

Direct numerical simulations of turbulent flows around a cylinder are performed using the virtual boundary technique to model the presence of the obstacle. This method consists of the imposition of a no-slip boundary condition within the flow field, using a specific forcing term added to the momentum equation. In this paper, two different inflow conditions are considered upstream from the cylinder. In the first case, where the inflow conditions correspond to a constant velocity flow, common features of the cylinder wake dynamics are well recovered (three-dimensional vortex shedding) while turbulent statistics (mean velocity and Reynolds stresses) are in good agreement with previous experimental and numerical results. This clearly shows that a code based on high-order finite difference schemes combined with the virtual boundary method can lead to reliable results even if the grid is not well designed for the shape of the obstacle. In the second case, the inflow conditions correspond to a spatially developi...