Advanced Experimental Methods for the
Analysis and Aerodynamic Design of Heavy
Vehicles
Mike Camosy, Andre Brown, Henri Kowalczyk, Gaylord Couthier
Auto Research Center, USA
[email protected]
Abstract Extensive knowledge exists in the testing of 1/8th scale, Class 8 tractor
trailer models within fixed floor wind tunnels. This size of model has proven to
correlate well with in a Reynolds number ranging between 1M and 6M. Prior testing is well documented on a Generic Conventional Model (GCM) in the NASA
AMES 7x10ft and 12ft wind tunnels. Within this prior research into Heavy Vehicle Aerodynamics, it has been identified on numerous occasions that improved accuracy will allow for greater understanding of the flow field structure in the underbody and internal flow regions. The aim of this paper is to summarize the new
research conducted at the Auto Research Center (ARC), a 50% rolling road scale
wind tunnel facility in Indianapolis, Indiana. ARC has tested a rolling road 1/8th
scale tractor trailer at 50m/s constant dynamic (approximately 1M Re). The model
features fully articulated suspension & axle systems, engine bay detail for internal
flow simulation, realistic radiator blockage, and an automated model motion system capable of controlling the model in roll, heave, pitch & yaw. To remain consistent with the previous testing conducted by NASA AMES, a replica of the
GCM tractor and trailer shapes were used for the upper aerodynamic surfaces. The
test objectives initially included a demonstration of correlation between the ARC
and NASA wind tunnels with the rolling road switched off. This baseline is then
compared to data obtained with the rolling road on, allowing the impact of 18 rotating wheels & tires on the flow structure to be visualized and analyzed. Further
studies are presented on the effects of improved detail in the underbody regions,
and on the effects of internal & cooling flows as applied to the GCM model. Future work at ARC will use detailed cab bodywork for analysis of specific OEM
tractors & trailers.