Random Aerodynamic Video Thread

[kach22i]

Maybe somebody can read these numbers and write them down, and then tell me what the 1mm lowering of the aft edge actually results in.

Just too early in the morning for me.


Clay model wind tunnel test Roof height vs Cd
Yoshi Suzuka

https://www.youtube.com/watch?v=1V_A1rsLsfs

Small clay model car in the small wind tunnel,
see how accurate they can measure Cd and Cl.
For pre-selection of overall shapes, general aerodynamic development, accurate enough for majority of tests.
Suzuka Racing Svc.

[freebeard]

I remember the name Suzuka. 78.9 to 75.9

• 78.9 -- 0.244 Cd 0/300 adj
• 77.9 -- 0.241 Cd 0.297 adj
• 76.9 -- 0.238 Cd 0.294 adj
• 75.9 -- 0.235 Cd 0.291 adj

[kach22i]

Originally Posted by freebeard

I remember the name Suzuka. 78.9 to 75.9

• 78.9 -- 0.244 Cd 0/300 adj
• 77.9 -- 0.241 Cd 0.297 adj
• 76.9 -- 0.238 Cd 0.294 adj
• 75.9 -- 0.235 Cd 0.291 adj

I think the whole point of that exercise was to show three things, Clf (lift front), Clfr (lift rear), and Cd (Coefficient of Drag). I was not in the proper state of mind yesterday morning (headache) to transcribe the jittery camera work into something more legible. Going to give it a second try.

Suzuka.....the name does sound familiar, the other one I was all excited about is Takuya Yura.


EDIT:

I was starting to write down the numbers from the blurry shaking video, then realized he was making it easy with the chart afterwords.

Clay model wind tunnel test Roof height vs Cd
Yoshi Suzuka


From this single example one might overreach and conclude that lift is a consequence of making a body more aerodynamic, an argument we have debated in the forum more than once before.

For me, it solidifies that the direction I took on my pickup truck to increase safety and road holding ability was the right one. I got my desired downforce without increasing fuel consumption, a small miracle.

[Phase]

Wonder if I should take my spoiler off and just extend and lower my rear roof line on my Ioniq then add a little flippy spoiler at the end

[aerohead]

No matter how much science you throw at some people, it appears to be impossible to move the dial on aerodynamic 'folk knowledge.'
Lift, created at the windshield header can be completely eliminated by the aft-body roofline, if it's streamlined, and reaches far back enough for pressure recovery to act against the top.
By carefully lowering the roof, without separation, the local streamline and boundary layer is exposed to higher ( Bernoulli Theorem ) pressure, as the flow slows along the diverging contour, getting closer to the undisturbed position it originally occupied, before the vehicle came along and displaced it.
This is why the 2013 VW XL1 can ( and has ) safely travelled at 112-mph without any spoiler ( while the original Audi TT was killing people ).

[aerohead]

Originally Posted by Phase

Wonder if I should take my spoiler off and just extend and lower my rear roof line on my Ioniq then add a little flippy spoiler at the end

I advise against it.
The existing tearing edge of the OEM rear spoiler is at the 'proper' elevation.
Any body extension needs to follow from there, and along the imaginary contour it defines, just as Hyundai does with the Ioniq 6.
If you extend from a lower point you invite separation, a cardinal sin in aerodynamics.

[freebeard]

Dog tracking?

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

Note the aero nose template at 3:29.

[aerohead]

'merican engine-uity'

[kach22i]

Originally Posted by freebeard

I remember the name Suzuka.

No video, but this photo has a name that popped out at me when I right clicked it.

Argo_JM19C_Ford_Suzuka
https://forums.pelicanparts.com/off-...ures-2645.html

[Phase]

Originally Posted by aerohead

I advise against it.
The existing tearing edge of the OEM rear spoiler is at the 'proper' elevation.
Any body extension needs to follow from there, and along the imaginary contour it defines, just as Hyundai does with the Ioniq 6.
If you extend from a lower point you invite separation, a cardinal sin in aerodynamics.

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?