PERRY, A.K., PASSMORE, M.A. and FINNEY, A., 2015. Influence of short rear end tapers on the base pressure of a simplified vehicle. SAE International Journal of Passenger Cars- Mechanical Systems, 8 (1), pp. 317-327.
This paper looks into the effect on base pressure of applying a high
aspect ratio chamfer to all edges of a simplified squareback model
(the Windsor model). The effects are investigated using force and
moment measurements along with surface pressure measurements on
the slanted surface and vertical base. The work forms part of a larger
study to develop understanding of the mechanisms that influence
overall base pressure and hence the resulting aerodynamic drag.
A short slant (approx. 4% of model length) was applied to the trailing
edges of the simplified vehicle model, representing the small rear end
optimisation typical of many real vehicle geometries. Two
experiments were performed: the first applied a chamfer at varying
angles to the top and bottom edges; the second test looked at the
same chamfer angle applied to the sides of the model geometry while
the top and bottom angle remained square. The changes in drag are
discussed and explained in the context of the base pressures and area
weighted pressure coefficients.