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Old 03-11-2020, 11:08 AM   #19 (permalink)
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Originally Posted by aerohead View Post
I went back and looked.Hucho is absolutely adamant about non-aspirated structures on road vehicles.Slots,slats,and spoilers can perform on an aircraft in 2-D flow,but never on an automobile in 3-D flow.Any boat tail or box-cavity must be airtight in order to function.Texas Tech's cab-wings were non-aspirated.
A permutation that is permissible is,to use a slot to pressurize an air-tight,fabric boat-tail envelope as I,and Bruce Ruefer (SP?) did.
I think a lot of study on slotted flaps (aircraft) and slotted wings (F1/Indy) race cars has been done after the mid-1980's.

However, I agree that the real world is 3D and very messy.

To clarify, the gentleman who so graciously did my CFD made no claims about the roof wing slot.

When I pushed him it was a concession of sorts, and visible in the graphic.

Just debatable about it's affect and meaning.

I wanted it to mean the slot introduced a high velocity thereby lower pressure area under the wing (more so than it would have with sealed leading edge), and that this promoted the air flowing over the top of the cab to collapse on top of it, which lead to the air mass encountering the truck bed cover slightly sooner, and making my rear Gurney flap all the more effective in producing down-force.

My slot was very small, not sure it had any affect larger than life as I would fantasize about on cold rainy days.

In this situation all we are trying to do is keep a rear window a bit cleaner.

To be honest, even with it slotted to the hilt, it's always going to be dirty - in my opinion.
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