Analysis of Drag Reduction Using Aerodynamic Devices on Commercial Buses by Computational Fluid Dynamic Simulation
Date
2015-09
Authors
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Journal ISSN
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Publisher
Kazuo Inamori School of Engineering at Alfred University.
Abstract
A large percentage of the usable fuel employed in a commercial bus is utilized to
overcome the aerodynamic drag at highway speeds and therefore if reduced could produce
a large reduction in the total fuel consumption of the vehicle and reduce the negative
environmental effects. MCI's D4505 coach bus was modeled in this study and airvanes,
drag reduction devices, were employed on the model bus to reduce the drag coefficient of
the bus. Each airvane, attached to edges of the leeward face of the bus, was optimized by
a parameter study were each individual dimension of the device was tested to determine
the optimal design. The airflow surrounding the bus models with and without the airvanes
attached were modeled using a computational fluid dynamics software. In this software
different turbulence models and meshes were employed to observe the effect of these
changes on the predicted airflow and optimization of the aerodynamic devices. Two
separate sets of simulations were run on each dimension tested. The first simulation
utilized a polyhedral mesh with the Realizable k-ε turbulence model, while the second set
of simulations used a CutCell mesh and the Shear Stress Transport k-ω turbulence model.
It was found that to reach a maximum reduction of the drag coefficient of the bus airvanes
were placed on all edges of the leeward face and optimized for the specific placement on
the bus. A drag coefficient of 0.54351 was produced which was a reduction of 12.37% for
the polyhedral RKE model while the CutCell SST model produced a drag coefficient of
0.54021 a reduction of 14.55%. This reduction in the drag coefficient lead to a maximum
reduction of 1.5% in the fuel consumption, which if applied to all commercial buses would
have a significant effect on the total national fuel consumption and a positive impact on
the environment.
Description
Advisory committee members: Wallace Leigh, Joe Rosiczkowski. Dissertation completed in partial fulfillment of the requirements for the degree of Masters of Science in Mechanical Engineering at the Kazuo Inamori School of Engineering at Alfred University
Type
Thesis