Best air curtain position?

[holypaulie]

My aero experts, what would be the best air curtain in my configuration? Yellow horizontal slits in my fog light cover or red vertical slit next to it? The fog cover is high pressure area which would be good to release it, vertical is right at the curve corner of bumper on the other hand. Exit channelled air would hit the end of front tire as well. Is this configuration possible to work? I'm thinking to build external ones but prefer internal for stealth look. What mpg I can gain out of those?

[freebeard]

One would guess......

Your two red slots are the same size. It needs to be a converging duct to accelerate the air. The shape is macht nichts but being inside the Faschenfeld edge would be beneficial.

Gain TBD.

[holypaulie]

Originally Posted by freebeard

One would guess......

Your two red slots are the same size. It needs to be a converging duct to accelerate the air. The shape is macht nichts but being inside the Faschenfeld edge would be beneficial.

Gain TBD.

Thank you very much for your input freebeard! What ratio between intake/vent of air curtain would you recommend for the best effect, is wider intake better? What and where is Faschenfeld edge?

[freebeard]

A converging duct has a smaller outlet; ratio TBD. Eyeballing some examples suggest about 1.5 to 1.

aerohead has documented the Fachsenfeld edge, I can't even spell it. Normally, it's the rear edges, and intended to suppress buffeting. My usage is ad hoc.

[aerohead]

I know the least about them as anyone, so I've provided a link to their genesis.
The original BMW design may have been predicated upon the entire front of the tires being inboard a bit, and shielded by the fascia, in the 'lee' of the wheel arch, inner fender well, with zero air actually attacking the tire face at all.
And I suspect that BMW was looking for a specific air velocity in the 'curtain', with respect to road velocity / air velocity.
https://www.press.bmwgroup.com/globa...nology-11-2012