Quote:
Originally Posted by Vman455
Yes. If he really didn't adjust the size (it looks like the dimensions are 1/10 what they should be), that will throw off the Reynolds number, which is proportional to length, and you won't get an accurate modeling of the airflow over the real truck unless you increase fluid speed to compensate.
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I believe you can get close with a model but you also have to scale the speed down the same. It sill will give a .05-.1 higher Cd even then. Better would simply use the real height and width as it's not a real wind tunnel but a computer simulation.
If it's already over .3 then adding wipers and mirrors is not going to get any better. Only if by "extreme" they mean ditch the fender flairs, keep the tires inside the body and maybe even flatten the roof. The roof may not change the CD much but dropping 3-4 square feet off the frontal aera will be even better.