Salt Patterns...

[donee]

Hi All,

I probably wont get a picture of this before it rains, but I have an interesting salt-pattern on the side of my car right now. The car is mostly free of salt, except in an long triangular area starting at a point from the top of the front wheel well, and proceeding slightly downward along the door and terminating in the middle of the rear door at about 6 inches wide. This salt is much more dense, and is almost perfectly white in places on the blue car. Its almost like it was painted on for styling. I did not notice it till I noticed someboody looking at it. It does look, at a distance, like its put on in purpose.

I think this is some kinda vortex eminating from the wheel well.

I am running my flush hubcaps.

Could this mean, that with the flush hubcaps, that only a flat flexible well cover between the well and normal height of the tire and maybe 10 inches long yeild allot of aero improvement? Or maybe a front 2/3's cresent shapped well cover?

But the other point of view is that the air coming around the outside of the car stalls there, and the small amount of air coming out of the wheel well going sideways starts a vortex.

This only occurs on the front wheels. Off the back wheels there is slightly denser salt pattern behind the well, but its evenly distributed from the bottom of the body to most the way up the wheel well.

Also, saw an Audi TT today with VG's acorss the back of its green-house. Good Idea, those cars aparently lift at high speeds. THey were about 3/4's of an inch high, delta shapped, and about 1 1/4 inch long. They were progressively angled outward towards the sides of the car. There were maybe 10 of them altogether. This was similar to the Mitsubishi EVO installation, but were smaller in size.

[aerohead]

Donee,my guess is that air escaping from the engine bay,out through the front wheel-wells is picking up water from salted roads ejected from the tires.In a rain you may have noticed spray blasting out of this area on other cars.Anyway,the water evaporates as you drive,leaving the salt residue in this area of spray,held close to the car by the surrounding undisturbed air.---------------------------------------------------- A car like basjoos Aero Civic wouldn't have this,as the front wheels are faired in.

[MetroMPG]

FYI, you can observe the airflow immediately aft of a front wheel well (with smooth hubcap) in this video I made to visualize the difference between "stock" and with a front wheel skirt.

It's pretty clear that adding the skirt reduces downstream turbulence.

And I think you may be right in thinking there may actually detached flow just aft of the wheel arch.

http://www.youtube.com/watch?v=Lo3EEHDoUgc

From this thread: http://ecomodder.com/forum/showthrea...etro-5403.html