On-Road Measurements of Aerodynamic Lift Compared With Wind Tunnel Data

Document Number: 960900

Date Published: February 1996

Author(s):
G. M. LeGood - Rover Group Ltd.
A. McArthur - Rover Group Ltd.

Abstract:
The principal development tool for the vehicle aerodynamicist continues to be the full-scale wind tunnel. In the absence of a reliable alternative, it is expected that this will continue for many years.

As a true simulation of conditions on the road, the conventional full-scale wind tunnel has limitations. In most cases the ground is fixed relative to the vehicle allowing an unrepresentative boundary layer to develop, the wheels of the test vehicle do not rotate and there is some uncertainty over the influences imposed by the tunnel walls. These factors are known to influence measured aerodynamic data.

This paper describes a technique for the measurement of aerodynamic lift on the road. Results for a medium-sized European passenger car are compared with measurements made in a traditional full-scale fixed ground wind tunnel. While there was found to be reasonable agreement between the road and wind tunnel values of total lift, the distribution of lift between front and rear axles was noticeably different. On the track, more front lift and less rear lift were measured compared to the wind tunnel.

The technique for measuring lift on the road was originally developed to help substantiate assumptions made in the comparison of track and wind tunnel derived aerodynamic drag data~the subject of a previously published paper.

In their own right, the results published in this paper contribute to the continuing investigation of the simulation problem within the automotive aerodynamics community, particularly as there is little published data of road derived lift measurements for passenger cars.

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Product Status: In Stock

See other papers presented at International Congress & Exposition, February 1996, Detroit, MI, USA, Session: International Congress & Exposition

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