View Single Post
Old 12-14-2009, 04:23 PM   #9 (permalink)
Piwoslaw
aero guerrilla
 
Piwoslaw's Avatar
 
Join Date: Oct 2008
Location: Warsaw, Poland
Posts: 3,750

Svietlana II - '13 Peugeot 308SW e-HDI 6sp
90 day: 58.1 mpg (US)
Thanks: 1,336
Thanked 749 Times in 476 Posts
Quote:
Originally Posted by orange4boy View Post
I think of it like the sugar cube-egg analogy. A tire is a blunt sugar cube rectangle in section. If you round out the sides, you are theoretically reducing detached flow which should reduce the wake. You can go from the cube up to as big as the egg and still have lower drag in that example.
I read in an aerodynamics book about research on lowering the Cd of busses that one of the options was to add a bulge in the front, where the airflow separates behind the windshield. From what I can remember, if the bulge is the correct size and shape, the airflow may stay attached, slightly reducing Cd. But the gain is less than what is lost to the increase in frontal area.
That is for busses. I've no idea if it's the same for a wheel that is rotating in a turbulent wheelwell.
As Thatguitarman said, it's all comes down to the individual car's aerodynamics. How close to attached is the airflow before and aft of front wheel?
I wonder if tuft testing a wheel while driving is possible (I don't mean the spare )?
__________________
e·co·mod·ding: the art of turning vehicles into what they should be

What matters is where you're going, not how fast.

"... we humans tend to screw up everything that's good enough as it is...or everything that we're attracted to, we love to go and defile it." - Chris Cornell


[Old] Piwoslaw's Peugeot 307sw modding thread
  Reply With Quote