Drag Force Analysis of Vehicle Roof Accessories

Broad, Jacob (2019) Drag Force Analysis of Vehicle Roof Accessories. [USQ Project]

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Roof racks are extremely helpful devices that allow large, bulky objects to be attached to the roof of a vehicle. They are generally utilised for extended trips when extra equipment and supplies are required. By design, roof racks and additions do not exhibit any aerodynamic features and can therefore increase the drag force and subsequently the fuel usage experienced by a host vehicle significantly. This issue is somewhat under-stated in the literature. This project aims to analyse the drag force of a vehicle without a load and compare it to a vehicle fitted with roof racks and a load. Next, some load modifications and optimisation will be displayed to evaluate the effects on drag force and fuel economy.

The project used ANSYS computer software to investigate the drag increase caused by roof racks and a load. Wind tunnel testing was performed to verify the Computational Fluid Dynamics simulations before official results were obtained. The results showed a constant drag increase of 47% for roof racks and a load across a variety of wind velocities, increasing the fuel usage of the vehicle by 3.5 L/100 km.

The load design was then subjected to four unique modifications which added material to the original load in order to reduce the drag force. Using ANSYS computer software, drag and flow visualisations were used to obtain the most effective load design. The dimensions of this design were optimised to reduce the drag force as much as possible. The final design enhanced the fuel economy of the vehicle by 1.5 L/100 km compared to the original load design. When considering a large journey of several days, this modification has the potential to result in significant financial savings.

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Item Type: USQ Project
Item Status: Live Archive
Faculty/School / Institute/Centre: Historic - Faculty of Health, Engineering and Sciences - School of Mechanical and Electrical Engineering (1 Jul 2013 - 31 Dec 2021)
Supervisors: Sharifian-Barforoush, Ahmad
Qualification: Bachelor of Engineering (Honours) (Mechanical)
Date Deposited: 26 Aug 2021 00:31
Last Modified: 26 Jun 2023 05:52
URI: https://sear.unisq.edu.au/id/eprint/43173

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