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Old 10-12-2020, 03:05 PM   #3 (permalink)
aerohead
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Quote:
Originally Posted by sgtlethargic View Post
It says "... shaping still has to be carried out almost exclusively by experiment [versus numerical methods]"
in "Aerodynamics of Road Vehicles."

A solar car article said they used CFD software.
The Full-Navier-Stokes Equation is the only numerical path to an accurate 1:1 scale representation of the real world, including all separation, turbulence, and the wake.
Hucho wrote in 1986 that this procedure was only then bordering on the possible, with the advent of supercomputers, and then, even requiring days to navigate a single iteration.
Daimler and BMW were using a watered down variety a decade or so ago, requiring almost 48-hours run time for a single iteration, whereas in a full-scale wind tunnel you can get a result in four minutes.
The beauty of CFD is that power requirements are that of only a 'village', as with a full-scale climatic wind tunnel they require the electricity of a 'city.'
The director for Lockheed's Marietta, Georgia wind tunnel told me in 1991 that every time they turned the tunnel on, the lights in the neighboring town all dimmed.
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