Stepped shape for flow attachment.

[dcb]

Originally Posted by beer

The fluid simulations show indeed that the louvres approach works...

It does? Seems like there is a lot more green behind each step. What specifically should one be looking at here?

Is the idea that as long as the louvers are long enough to allow reattachment, that there is no penalty?

[dcb]

Here is one logical extreme on stepped shapes, I think there is far more to it than "following the aerodynamic outline" but don't know. Does the size of the steps matter? What would be the difference in CD of these two?

[Frank Lee]

Yeah, that's too extreme a "louver" and Cd would suffer. I think the key is to have the spacing close enough together to have nicely trapped rolling vortices of the sort with lateral axis', like in a pickup bed.

Louvers won't be as good as "template" but they're better than nothing. I think the XR4ti double plane spoiler is sort of a quasi-louver.

[dcb]

Well that is the problem, the hungarian car has small steps, almost like "why not make it smooth?" and the mirror is even smaller. CFG,s videos offer no sense of scale that I can tell.

It seems intuitive to me that there is a penalty for stepping, and that it is a function of step size, just can't explain it very well or write out that function.

[NeilBlanchard]

Here's the English version of the Antro webpage:

Antro

Their car also has the steps below the 'A' pillar:

[JasonG]

Why not just drive in reverse? Nice shape but too much hype and fluff on their website.

[dcb]

I'm hoping Phil will chime in here regarding the effect of step size and increase in drag... The steps on that antro are tiny.

[Patrick]

Originally Posted by NeilBlanchard

Here's the English version of the Antro webpage:

Antro

Their car also has the steps below the 'A' pillar:

It looks like those louvers go the wrong way. My guess is it's some kind of intake, probably for cabin ventilation air.

[ChazInMT]

I'm guessing the folks at Antro have NOT been looking at the ecomodder website. If they put there egg in the wind tunnel backwards, with a block on the unsusally huge area between the rear wheels to keep the air from going underneath, I bet they'd go Hmmmm.

[HighMPG]

Originally Posted by beer

@cfg83
another pic of louvres on the "rear hood" of a ferrari f40

I believe this is more for ventilating the engine bay lads.
As air passes over it sucks air out from inside the engine bay.