Quote:
Originally Posted by RiderofBikes
Front VG's?! yeah my fiesta mirrors were what i first thought of... But the shape itself, is nice and aero already, I think the main point to them was to reduce wind buffeting for a quieter presence. On the otherhand, IF those small, i mean small strifes are enough to create vortices, then why are all the others we see commercially produced so, huge! If you look at it, even the EVO's arent that big.
Also there is difference to the golf ball theory, because not all model of balls # of dimples/size/depth/dimple pattern are the same.. and the fact its not in ground effect while in flight. make for huge inconsistancies...
If this were the same case with VG theory, then why dont my mirrors have strifes on the bottom(technically there not in ground effect)? as well as on wings/spoilers? |
The size of the trip is proportional to the object size & length, I believe it is related to the thickness of the boundary layer, which gets thicker the further down the boundary layer you go.
As a guesstimate
A mirror may only require a few 3mm (1/8") of disturbance.
A small car, say 6mm (1/4")
A van maybe 12-25mm (1/2 to 1")
and a large truck 25 - 40mm (1-1 1/2")
The other complication is the boundary layer gets thicker as velocity increases (think that's right), so the scaling is crucial, something that trips the boundary layer at HWY speeds to get a drag reduction may just result in excess drag at lower speeds because it is causing turbulence in a smooth flow, so there is a bit of a juggling act.