02-14-2011, 05:57 PM
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#6 (permalink)
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Master EcoModder
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Quote:
Originally Posted by Piwoslaw
Here is what I found in Piechna's book:
According to Carr ([1], nice last name in this field of research, btw), for modern cars the coefficient of surface drag is around 0.08. For a mid-sized passenger car the coefficient of lift is 0.15, which implies that the edge vortex drag coefficient is 0.01 (assuming that coefficient k in Carr's formula is equal to 0.5).
Based on these assumptions, a typical drag coefficient of Cx=0.30 could be decomposed in the following ways:
| . | delta Cx (Barnard, [2]) | delta Cx (Katz, [3]) | | Surface drag | 0.08 | 0.04-0.05 | | Air pressure drag | 0.10 | 0.00-0.45 | | Wheels | 0.08 | - | | Engine cooling | 0.03 | 0.00-0.06 | | Internal airflow, ventilation | - | 0.00-0.05 | | Edge vortices | 0.01 | 0.00-0.60 | | Total | 0.30 | - |
[1] Carr G.W., Potential for aerodynamic drag reduction in car design, Impact of Aerodynamics on Vehicle Design, Proc, International association for Vehicle Design: Technological Advances in Vehicle Design, SP3, ed. Dorgham M.A., 1983, pp.44-56.
[2] Barnard R.H., Road Vehicle Aerodynamic Design, Longman, 1996.
[3] Katz J., Race Car aerodynamics, Robert Bentley Automotive Publishers, 1995. |
In the past,'Interference Drag' and 'Induced Drag' were parameters for the aerodynamic drag makeup.And any longitudinal vortices would be embedded within the profile drag component.
This is my first exposure to the term 'edge vortex',I've never heard of it in 35 years of study.  |
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