Title: Vehicle aerodynamics - force and moment measurements on scaled car models using stationary and moving-belt ground planes

Authors: E. Olsen, E. Olsson, G. Johansson

Addresses: Department of Applied Thermodynamics and Fluid Mechanics, Chalmers University of Technology, Goteborg, Sweden. ' Department of Applied Thermodynamics and Fluid Mechanics, Chalmers University of Technology, Goteborg, Sweden. ' Department of Applied Thermodynamics and Fluid Mechanics, Chalmers University of Technology, Goteborg, Sweden

Abstract: The lift and drag forces and the pitch moment for scaled car models are measured. The measurements are carried out at different heights above a floor, for different after-body shapes, and at various air velocities. The results of the measurements show that the boundary layer on the floor has a marked effect on the lift and drag coefficients and on the pitch moment coefficient. The measurements also show that there are small variations of drag with Reynolds number when the floor is stationary, and slightly more when the floor is moving. The lift force increases, or is nearly constant, as the Reynolds number increases except at base slant angle φ = 40°, where there is a complex variation with Reynolds number. The pitch moment exhibits a nearly steady increase in value when the Reynolds number increases. The moving floor generally gives higher drag and less lift force and higher pitch moment than the stationary floor. A base slant angle of between 30° and 40° gives a maximum in drag force and pitch moment. The lift force decreases in a complex pattern as the base slant angle increases.

Keywords: vehicle aerodynamics; force measurements; moment measurements; scale models; vehicle design; wind tunnel tests; Reynolds number; modelling.

DOI: 10.1504/IJVD.1988.061483

International Journal of Vehicle Design, 1988 Vol.9 No.2, pp.226 - 241

Published online: 26 May 2014 *

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