The Aerodynamic Performance of Automotive Underbody Diffusers National Research Council of Canada

Format:

Conference/Event

Author/Creator:

Cooper, Kevin R., author.

Conference Name:

International Congress & Exposition (1998-02-23 : Detroit, Michigan, United States)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 1998

Summary:

This paper examines the aerodynamic behaviour of plane-walled, single-plane-expansion, underbody diffusers fitted to a wind-tunnel model of a wheel-less, simple body having automobile proportions. The measurements were performed over a moving-belt assembly in the Pilot Wind Tunnel of the National Research Council of Canada (NRC). The purposes of the investigation were:The paper concentrates on the physics of the underbody flow in an attempt to understand diffuser behaviour in this application and its effect on downforce and drag, and to gain new insight into the relative characteristics of different vehicle ground simulations.The data are analysed from the diffuser perspective by relating the measurements to the conventional diffuser parameters of area ratio, non-dimensional length and flow-area blockage. This last parameter, which represents the velocity non-uniformity in the inlet flow due to boundary layers on the underside of the model and on the tunnel floor, is one that may contribute to diffuser performance differences between the fixed-ground and the moving-ground simulations.A performance characteristic defining diffuser geometries for maximum downforce has been identified. Knowledge of its functional behaviour offers the possibility of developing similar curves for new vehicle geometries with a reduced number of measurements or computations.The data acquired demonstrate that an underbody diffuser can significantly increase downforce, and can provide some drag reduction if ride height is not too small

Notes:

Vendor supplied data

Publisher Number:

980030

Access Restriction:

Restricted for use by site license