Random Wind Tunnel and Smoke Pictures Thread

[aerohead]

Originally Posted by Cd

After a fresh rain, I can clearly see the large vortex behind the cab on semis that are driving without their trailer.
I tried to get a video, but the contrast does not show up well.
Surely you all have seen this as well ( and the previously mentioned vortexes coming from wheelwells )
Once, I even was able to see a plastic bag that was caught in this vortex. It looks like a small tornado just behind the cab of the semi.
The airflow starts at the chassis just in front of the rear wheels and spirals upwards to the roof of the vehicle.

We have a section of divided, 4-lane, backed by a long row of evergreen trees. From the proper vantage point, this dark background really makes the water mist 'pop'.

[kach22i]

Some CFD action, the pretty colors can be artful at times.

PDF Download Paper.
Aerodynamic performances of rounded fastback
https://www.google.com/url?sa=i&url=...AAAAAdAAAAABAO

[kach22i]

More CFD action..................

Figure 42- uploaded by Pete Bachant
https://www.researchgate.net/figure/...ig37_315865543

Contours of velocity magnitude generated using the steady, k-ω SST turbulence model for moving ground cases.

Convertible Aerodynamics
http://sersol.weebly.com/workshop/ca...e-aerodynamics



The COANDA Flow Control and Newtonian Concept Approach to Achieve Drag Reduction of Passenger Vehicle
Jung-Do Kee, Moo-Sang Kim and Byung-Cheon Lee
https://www.jstor.org/stable/44730994?seq=1

[freebeard]

I've been a fan of Coanda since I read about his 'afterburner' airplane.

Click for video

That third CFD appears to have a trunk-mounted spoiler. This windshield header device seems to be a diverging duct which would retard [if I can use that word] the air that wants to wrap around the header. youtu.be/ZDpScek3KBc?t=92 Here's it shown without the rear baffle plate.
That is surprisingly narrow, no wider than the headrests.

[freebeard]

I've been saying that the most promising tool for CFD is Blender. Here is a nine second example that uses the Starship:

Flow simulation 600,000 fluid particles hit the surface of the animated SpaceX Spaceship.

[AeroMcAeroFace]

Originally Posted by kach22i

To me smoke pictures are relaxing, like watching a babbling brook, not of lot of hard data though.

Not technically a wind tunnel or a smoke picture, but certainly interesting, and kach22i will be relaxed.https://www.instructables.com/Turbulent-Flow-Christmas-Ornaments/

[kach22i]

Originally Posted by AeroMcAeroFace

Not technically a wind tunnel or a smoke picture, but certainly interesting, and kach22i will be relaxed.https://www.instructables.com/Turbulent-Flow-Christmas-Ornaments/

Just under half that speed would suit me, when it flows that quickly it's too much like fire and raises anxiety.

[freebeard]

It would be easy enough to shorten the propellor blades as needed. I would have liked a picture showing how to get the propellor through the neck of the ornament.

Don't use red food coloring.

[kach22i]

Next-gen 911 GT3 secrets revealed! Race car aero and more variants
By Andy Enright, 20 Aug 2020 News
https://www.whichcar.com.au/news/202...crets-revealed

If you’re the sort of person who has been poring over the photographs shot through the fence at Brunnchen corner on the Nurburgring, you might well be aware that Porsche has been experimenting with a number of divergent aerodynamic packages for the 992 GT3...................

By fitting a swan-neck rear wing, they were able to claw back 16 percent of what was looking like a 34 percent loss of downforce through downsizing the wing.

In other words, Porsche may well realise a downforce benefit of somewhere in the region of 16 percent by fitting the swan-neck.

WHY A SWAN NECK?

Ever wondered why aircraft sling the engines under the wing instead of on top? That’s because on a plane, the top side of the wing is the important part, speeding the air, creating low pressure and thus lift. That area needs to be uninterrupted. Think of a racing car wing as an inverted aircraft wing and you begin to wonder why it took so long for items with unencumbered undersides to appear.

[kach22i]

Intake Air: Does Velocity Choke It? - Pelican Parts Forums