Computation of the Flow Around a Simplified Car Using the Rescaled

v²

–f Model

The Ahmed body is a simplified car used in automotive industry to investigate the influence of the flow structure on the drag. When the angle of the hatchback approaches 30°, the wake of the body experiences a transition from a quasi-2-D to a fully 3-D structure, which is at the origin of a drag crisis. Many turbulence models have been tested for the case at 25° and none of them was able to reproduce correctly the complex flow structure. The paper aims at investigating the performances of a recently developed near-wall eddy-viscosity model, the rescaled v²–f model, which is derived from the well known v²–f model. It is shown that the model does not perform better than models of the same class. Indeed, the predicted wake is nearly 2-D, massively separated, which is characteristic of the low-drag configuration: the transition of the wake to a fully 3-D, highly dissipative structure is not reproduced.