Quote:
Originally Posted by Vman455
Calm down; I wasn't attacking you and you don't need to make threats. I was merely responding to this claim:
Which you then corrected in your next post anyway:
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From my archive, automotive rolling stock at the time of Bearman's July 23, 1979 REVIEW in the Journal of Fluid Engineering, possessed drag coefficients ranging from Cd 1.15, to Cd 0.178. Nearly the full spectrum.
It would have been impossible to make any all-encompassing, blanket statement about flow around automobiles.
In April 1977, Glenn D. Thompson of the EPA came out in favor of the 'template'.
Bearman's 1979 article eluded to the 'template' with his comment, ' where the boundary layer fails to withstand some critical adverse pressure gradient.'
Bearman goes on to share W.A. Mair's boat-tail schematic, with it's specific lead-in contour transitioning to the recommended maximum 22-degree slope angle ( the model for the aerodynamic streamlining template number-one ). Mair's data reflects only pressure drag. Viscous effects have been removed from the presentation. It has nothing to do with the viscous boundary layer, or boundary layer thickness.
The EPA's 1977 contour is the aerodynamic streamlining template number two.
Bearman goes on to describe the mirror-image, ground reflection from potential flow theory which explains Jaray's 1922, Cd 0.13, half- ( Zeppelin ) body automobile, which also pre-quantifies the drag of the 'template', as it's drag was published in 1923 by Prandtl, originator of both the Sch'o'rwagen, and 'Lange' car.
In Bearman's preamble to his 1979 review he speaks of 'complex' body shapes of which flow would be difficult to predict. No objection to that. The 'template', however is a simple, non-complex body. It is streamlined. It's a known quantity. There's nothing abstract or hypothetical about it. It's in perfect agreement with boundary layer theory. And it's exactly what Hucho is speaking to in relation to a path forward towards sub- Cd 0.10 automobiles. It's not a matter of technical feasibility. It's not a conspiracy theory.