Effect of the traversing unit on the flow structures behind a passenger vehicle

Paper in proceeding, 2014

In the wind tunnel a common method for wake analysis is to attach a pressure probe to a traversing unit in order to retrieve flow field information. However, the approach is intrusive and has a direct impact on the surrounding flow field, affecting the investigated flow characteristics. In measurements conducted in the Volvo Cars Aerodynamic Wind tunnel, the forces measured by the balance system showed variations depending on the position of the traversing unit in the wake. In this paper, a numerical investigation is conducted to initially validate the wind tunnel results and to give more insight into the physics of the problem. The numerical results show similar force variations compared to the wind tunnel. In addition, CFD reveals surface pressure and flow structure differences associated with the different locations of the traversing unit.