Simulations of bluff body wakes and vehicle aerodynamics

Paper in proceeding, 2013

The paper discusses how flow-resolving LES simulations are used to predict and explain flows around vehicle-like bluff bodies. Several different applications of the LES are presented including bodies in unsteady winds, flow control and asymmetry phenomena of the wake behind notchback geometries. The focus of the paper is in explaining the flows around vehicle-like bluff bodies using numerical simulations. Differences between results of dynamic and quasi-steady tests are studied and the flow mechanisms responsible for phenomena such as hysteresis, phase shift and overshoots of forces and moments are explained. Several different applications of flow control are explored and it has been shown that LES is useful as a tool for designing the means of flow control for drag reduction purposes. The last example of simulation of notchback geometry demonstrates the usage of LES to explain the phenomena of wake asymmetry in a symmetric geometric set- up. Although, the observation of such asymmetry is documented in the literature, the underplaying flow phenomena is unknown and the present LES gives first indications for the explanation of the undelaying flow mechanism.