Abstract
Certain aspects of Aeronautical and Building Aerodynamics research are shown to be applicable to the study of the flow around road vehicles. Road vehicles are exposed to the natural wind and the possible effects of free stream turbulence on the mean flow are discussed. A review is given of the effects of turbulence on the drag of bluff bodies with separation from sharp edges, and with separation from continuous surfaces. A road vehicle moves close to a ground plane and the influence that this may have on the flow is examined. Experimental results are presented of the forces acting on an idealised vehicle shape in “ground effect” and they demonstrate the importance of ground clearance. The results also expose differences between wind-tunnel measurements made with a moving wall and a fixed ground plane. Finally a two-dimensional, free-streamline theory is used to predict, qualitatively, the experimental results.
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Abbreviations
- A:
-
pLate frontal area
- CD :
-
drag coefficient
- CL :
-
lift coefficient
- Cp :
-
pressure coefficient
- Cpb :
-
base-pressure coefficient
- c:
-
body length
- D:
-
depth
- H:
-
height
- h:
-
ground clearance
- Lx :
-
longitudinal scale of turbulence
- U:
-
wind speed
- \(\sqrt{{{{\bar{u}}}^{2}}}\) :
-
r.m.s. horizontal wind-speed fluctuations
- V:
-
vehicle speed
- W:
-
body width
- x:
-
streamwise coordinate
- α:
-
angle of incidence
- δ*:
-
boundary-layer displacement thickness
- ∈:
-
ground-clearance/body length;≡ h/c
- k:
-
circulation
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© 1978 Plenum Press, New York
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Bearman, P.W. (1978). Some Effects of Free-Stream Turbulence and the Presence of the Ground on the Flow Around Bluff Bodies. In: Sovran, G., Morel, T., Mason, W.T. (eds) Aerodynamic Drag Mechanisms of Bluff Bodies and Road Vehicles. Springer, Boston, MA. https://doi.org/10.1007/978-1-4684-8434-2_4
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DOI: https://doi.org/10.1007/978-1-4684-8434-2_4
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