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Old 10-11-2020, 03:48 PM   #2 (permalink)
JulianEdgar
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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.
Professional level CFD is used by all major car manufacturers, solar car designers, etc, to develop shapes. However, from what I understand, there is a major difference between CFD of the sort available free and at low cost - and the professional level stuff.

Professor Joe Katz was scathing about low cost CFD. He said to me: "It's just kids with pretty pictures."

Rob Palin (ex Tesla) is currently using a professional version of a low cost CFD to do some modelling. It was taking his PC (he gave the spec - overclocked and high quality) three days to churn out 10 seconds of airflow modelling.

If you look around the web you'll find people modelling current cars with low cost CFD - and their calculated Cd values are often very different to the manufacturer's quoted Cd value for the car.

I am no expert in this area, but as far as I can tell, CFD isn't yet viable at amateur level for results that you'd trust. I'd love to see some comparison testing between low cost CFD and full-size testing of the car.
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