Drag Reduction of a Simple Bluff Body by Changing The Rear End
Paper i proceeding, 2009
The flow field around bluff bodies constitutes a classic area
within fluid dynamics and has been the topic for much research
through the years. However, in the use for road vehicles with
the effect of the ground, the behavior is changed very much
from more classical aviation usage. In this paper we are
investigating the drag force reduction on a vehicle like
simplified model with rear open diffuser when stationary
ground simulation is considered.
The objective with this work was to study the rear end of a
bluff body and optimize it for drag with ground vehicle like
boundaries. Here the testing contains two common body
variants, square back, boat tailed/fastback in generic forms.
Scale model testing combined with simulations is used to
explain behavior and flow field. The model testing is
performed in the L2 scale model wind tunnel at Chalmers
University of Technology in Gothenburg, Sweden. Simulations
are done with the commercial CFD code Fluent.
A diffuser on a car is normally used to create down force
but here it is tested to see if the energy in the flow can be used
to optimize reduction of drag. One part of the study is to show
the potential in optimizing the rear end underbody for drag, by
varying the diffuser angle.
The results show a potential in drag reduction by using a
diffuser and varying effect depending on other rear end