Nature wind tunnel optimization
 

snow + wind =

http://www.student.oulu.fi/~torvinen...nnel-astra.jpg

I guess what he needs to do is run out there with some fiberglass and resin and capture that otherwise unattainable shape for posterity.

Wind deposits and/or sculpts snow along stagnation points. It would be interesting to wind tunnel test that car with and without the shape created by the snow. I'll bet it's less draggy with the snow.

It's worth noting that the deposition and removal of snow is also highly dependent on the surroundings and the wind condition at the time of said deposition or removal.

The shapes obtained by this process are aerodynamic specifically to the conditions at the time of creation. In other circumstances, they're less than optimal.

Even if the new shape has lower Cd, then the extra snow may have increased FA.

Would a Sunraycer parked outside not accumilate any snow :confused: :p

I bet it would. Depending on how the wind was blowing, and what environmental influences were at play.

Don't believe me, park a Durango behind one, then tell me if it's got any snow on it after a good snowy windstorm.

I'll do that! :p

What I meant, though, is that the snow could be showing you a good shape.. it could also be showing you a crappy shape because of some interference.

Without a basic knowledge of aerodynamics, you'd never know the difference.

And that's why people end up with misconceptions about pretty much anything.

...Mother Nature has an intrinsic "way" of doings thing "right the first time" after millions of years of evolutionary "trial-n-error," for instance:

"EXAMPLE 10. Blood is transported in the body by means of arteries, veins, artioles, and capillaries. This procedure is ideally carried out in such a way as to minimize the work-energy required to transport the blood from the heart to the organs and back again. Consider the two blood vessels depicted in Figure 9, where r1 > r2." Thus, ie:

cos(phi) = (r2/r1)^(4)

...where:
phi = branch angle between the two vessels
r1 = radius of smaller vessel
r2 = radius of larger vessel

...one of the calculus exercises (page 391) in Grossman's CALCULUS, 2nd ed., 1981, Academic Press.

...she always takes the path of "...least (work energy) resistance..." and it's the same thing with snow and aerodynamics.

P.S.--this equation is VERY handy when you want to merge smaller pipe flow into a larger pipe flow with minimum turbulence and back pressure (ie: header pipes into collectors, etc.).