Flow Viz!

"ttyymmnn" (ttyymmnn)
09/27/2013 at 10:50 • Filed to: Planelopnik

Researchers at NASA's !!!error: Indecipherable SUB-paragraph formatting!!! in Hampton, Va., use all sorts of tools and techniques to learn more during the development of aircraft and spacecraft designs. In this photo, engineers led by researcher Greg Gatlin have sprayed fluorescent oil on a 5.8 percent scale model of a futuristic hybrid wing body during tests in the !!!error: Indecipherable SUB-paragraph formatting!!! . The oil helps researchers "see" the flow patterns when air passes over and around the model. Those patterns are important in determining crucial aircraft characteristics such as lift and drag.

Image Credit: NASA Langley/Preston Martin via !!!error: Indecipherable SUB-paragraph formatting!!!

DISCUSSION (15)

Arch Duke Maxyenko, Shit Talk Extraordinaire > ttyymmnn
09/27/2013 at 10:52

Or NASA engineers have discovered LSD.

Jayhawk Jake > ttyymmnn
09/27/2013 at 11:00

Holy high angle of attack batman!

Icemanmaybeirunoutofthetalents > ttyymmnn
09/27/2013 at 12:28

That stuff is beautiful

You can tell a Finn but you can't tell him much > ttyymmnn
09/27/2013 at 14:26

Kinja'd!!!

In case of Kinja I'm aiming for the big vortex at the wing root. That doesn't seem like it is a good thing. And the airflow over the wing is... it's going the wrong way.

ttyymmnn > You can tell a Finn but you can't tell him much
09/27/2013 at 14:27

I was wondering about those vortices too.

phillip > You can tell a Finn but you can't tell him much
09/29/2013 at 01:36

From my lessons in flight performance, typically those are intentionally created vortices used for high AOA lift and post stall type maneuvers. just google "vortex lift" ever see Concorde come in for a landing? vortex lift.

phillip > You can tell a Finn but you can't tell him much
09/29/2013 at 01:36

Rock Bottom > ttyymmnn
10/03/2013 at 16:28

Note: Oil Trace tests can tell you pressure deltas, not where the air is flowing. Common misconception. The oil will chase pressure gradients on the surface of the test article. Want proof? Look at the "vortex" where the fuselage chine meets the wing leading edge. Do you really think the air is flowing backwards and running laps there? It's not.

ttyymmnn > Rock Bottom
10/03/2013 at 16:31

I'm not doubting you, but the text is direct from NASA.

Rock Bottom > ttyymmnn
10/03/2013 at 16:38

While oil trace data is cute, it's also a few generations behind the latest flow visualation techniques. I'm thinking things like pressure sensitive paint (PSP), Particle Image Velocimetry (PIV), and Reverse Background Oriented Schlieren (RBOS).

A few years ago I was a test director for the UH-60 Airloads Test in the NFAC 40x80 ft Wind Tunnel. We used RBOS, PIV, Blade Deformation Photogrametry, and about 240 surface pressure transducers (along with an equal number of strain gages) to qualify and quantify the flow field around a "standard" type rotor system (the UH-60, narrow-chord blades) and correlate that flow field with blade deformation and blade loading. It was likely the most measurement-intensive wind tunnel test ever attempted and we're very proud of what we accomplished.

If you're bored, read about the test here: http://rotorcraft.arc.nasa.gov/Publications/f…

If you're REALLY bored, read about my facility here: http://www.nasa.gov/centers/ames/m…

And if you're insanely bored, here's a brief write-up I did a few days ago that has a few pictures and references to the 40x80 (our small test section): http://oppositelock.jalopnik.com/a-brief-histor…

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ttyymmnn > Rock Bottom
10/03/2013 at 16:43

I'm guessing you've got a little free time on your hands these days....

Thanks for the links. I missed your piece about tilt-rotor development. I look forward to reading it.

Rock Bottom > ttyymmnn
10/03/2013 at 19:11

I somehow managed to find myself on the "essential personnel" list, so I don't get any time off for bad behavior!

I'm just glad that people like you are helping to spread the word about these experiments! Most people seem to think that wind tunnel testing is dead and computers have replaced them. Keep digging up this great stuff!

Rock Bottom > ttyymmnn
10/03/2013 at 19:12

My bad, I didn't mean to come off sounding confrontational... I get a little moody before lunch! Great write-up and keep the wind tunnel love coming!

ttyymmnn > Rock Bottom
10/03/2013 at 21:14

Hey, no worries. I didn't think you sounded confrontational. I just wanted you to know I didn't write it! I'm a major airplane nut, but I'm a musician by training. That scientific stuff is all Greek—or Latin—to me.

Rock Bottom > ttyymmnn
10/04/2013 at 11:14

Regardless of your educational background, you have the passion and that's all that really matters!