A NUMERICAL INVESTIGATION OF THE TURBULENT WAKE OF A SQUARE-BACK BLUFF BODY USING WALL-MODELED LARGE EDDY SIMULATION

The Windsor model is a simplified automotive bluff body characterized by a square-back geometry, which is representative of a transport vehicle. It has often been used for research with interests in drag reduction techniques and wake analysis. The turbulent wake past a Windsor body is known not to carry the common key flow features seen in typical automotives: counter-rotating streamwise vortices, separation bubbles, and a recirculation region. Rather, its wake dynamics feature a more complicated set of dynamic modes that switch randomly over time. This research assesses wall-modeled large eddy simulation (WMLES) in the context of automotive aerodynamics, which is generally characterized by high Reynolds number turbulent flows of bluff bodies in close proximity to the ground. WMLES reduces the computational cost of resolving the inner region of a turbulent boundary layer by replacing the no-slip boundary condition with a wall model that estimates the wall shear stress. The flow past the Windsor body is investigated using OpenFOAM and a third-party WMLES library, libWallModelledLES. Tests are performed with a freestream velocity of 40 m/s at a Reynolds number ReH = 7.6 × 105. Results demonstrate that WMLES successfully captures the flow behavior and wake dynamics but is limited by a lack of temporal resolution due to the long-time evolution required for the Windsor body.