Random Aerodynamic Video Thread

[Piotrsko]

Not only tuft but trailing recording tape in the slipstream beyond

[kach22i]

Interested in crosswinds?

https://www.youtube.com/watch?v=UAe_zwX9NBM

[kach22i]

Unusual video, but he says a few things that are not true and does not completely understand the topic, still this video has something to offer if at least further research into the topics and techniques mentioned.

https://www.youtube.com/watch?v=wlJlayVteog

[kach22i]

Cool music?

I think it's the same video Aerohead posted earlier.

https://www.youtube.com/watch?v=E9ZSAX56m0E

[kach22i]

Why they chose a non-stock VW Beetle is a mystery.

https://www.youtube.com/watch?v=IsDUVXscCGg

[freebeard]

Since they don't actually say, I went to the comments.

David Droescher 5 years ago
reverse. by.15 cD
the wind screen is close enough to vertical to act as a truncated kam back, and the hood sticks out far enough to alow reattachment making the hole in the back of the doughnut smaller.

Who cares about the stock Beetle? This one has a proper stance.

[freebeard]

Youtube wanted me to see this one:

DIY Aerodynamics #1: a '70s VW Beetle

The burble at the windshield header exists because VW raised the windshield height in 1965. The 2D analysis at the rear doesn't disclose the inward vortexes that feed the engine air.

[aerohead]

Originally Posted by Phase

I could also tuft test it right too? Apparently some people complained about the Prius being too steep and would have flow separation but didn’t when it first came out.

Could anyone do a quick drawing or mock up of how I would extend the roofline then for Lower drag in my Ioniq?

Let me share some cautionary information from: MODIFYING the AERODYNAMICS of YOUR ROAD CAR: ( paraphrasing )
1) It is very hard to see trailing vortices. page-19
2) C-pillar vortices are linked to separation. page- 91
3) Flow separation at the trailing edge of the roof explains low base pressure. page- 79
4) Low base pressure explains high drag. page-80
5) A way in which a spoiler can reduce lift and drag is by simply promoting flow reattachment of separated flow. page-195
6) A spoiler can increase pressure on top of the boot and backlight. page-195
7) High base pressure explains low drag. page-80
8) raising the upper body's trailing edge up to the reversal point eliminates vortices, eliminates separation, decreases lift, and lowers drag. page- 19
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If Hyundai's aerodynamics and CFD team has succeeded in establishing the reversal point with the trailing edge of their OEM spoiler, then, any modification should proceed from this optimized location, and along the imaginary pathway it implies.
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Tuft testing, not revealing longitudinally-attached vortices, could easily deceive an investigator, who misinterpreted tufts, aligned from separation-induced downwash, to equate to 'attached' flow. Tufts pointing 'rearwards' are no 'proof' of attached flow. This is an issue for ANY vehicle with a factory rear spoiler.
Hermann Wurst's 'solution' to these issues should, in my opinion, serve as the gold standard for proper aerodynamic problem-solving.

[aerohead]

Not that much there for ecomodding.
The NSX' OEM spoiler tearing edge is very close to the AST-III. Rear lift would not be an issue. The vertical small addition would place it in direct downforce territory for sure.
In a recent side by side test with Porsche, MOTOR TREND came away saying that the NSX drove a lot better on 'paper', than it did in the real world.

[aerohead]

VW has provided a smoke-flow image, still photograph of the Bug in their climatic wind tunnel. Flow separates exactly where the tufts indicate.
The photograph is in a book about the NEW BEETLE.
https://www.pinterest.com/pin/57561701466034932/