Comparison of Numerical Simulations with Experiments of Bluff Bodies Including Under-Hood Flow 2011-01-0171
Computational Fluid Dynamics (CFD) is state of the art in the
aerodynamic development process of vehicles nowadays. With
increasing computer power the numerical simulations including
meshing and turbulence modeling are capturing the complex geometry
of vehicles and the flow field behavior around and behind a bluff
body in more detail. The ultimate goal for realistic automotive
simulations is to model the under-hood as well.
In this study vehicle simulations using the finite volume open
source CFD program OpenFOAM® are validated with own experiments on
a modified generic quarter-scale SAE body with under-hood flow. A
model radiator was included to take account of the pressure drop in
the under-hood compartment. Force and pressure measurements around
the car, total-pressure and hot-wire measurements in the car flow
field and surface flow patterns were simulated and compared with
the experiment. The simulations are performed using a virtual wind
tunnel which provides correct boundary-layer treatment and
test-section pressure gradient compared to the experiment.
Different approaches of turbulence modeling were investigated, RANS
and DDES simulations are performed and compared with each other and
with own experiments.
For industrial usage of the computation process, a porous media
for the model radiator was implemented and validated in OpenFOAM®.
A process including meshing, solving and post-processing was
developed and validated with experiments. The result is a
completely validated numerical process.