NASA Ames releases cool animation showing airflow on 777 landing gear

Nasa Ames (in my backyard) is looking at how to reduce aircraft noise. They are taking a hard look using supercomputers to model airflow around landing gear (In this case the front gear of a 777) and other surfaces in an effort to try to reduce noise. They are using the Pleidades Supercomputer that is ranked as #17 int he world in terms of speed.

a reply to: FredT

I SO want to visit their wind tunnel.

Kinda mesmerizing to watch. I too would love to visit their wind tunnel. Of course theyd probably kick me out for being annoying. Id be trying to put random objects in the tunnel just to see what kinda turbulance pattern it makes. Theyd be like "bass put the rhododendron back on the desk its not going in the wind tunnel!"

a reply to: BASSPLYR

Id put myself in first lol

originally posted by: Zaphod58
a reply to: FredT

I SO want to visit their wind tunnel.

We used to go all the time. Several of our dads in our Scout Troop worked there so we could walk the length of the big tunnel. Its also near one of my bike paths and you can hear it when you go by. Ill snap some shots next time of the exterior

a reply to: FredT

Not quite a wind tunnel but i got pacific gas and electric to take photos of me in high definition colored IR doing martial arts poses once. Turns out your ears and nose are much colder than the rest of your body.

Flagg...just for subject matter....he....he wait...how do they know......exactly....aww, they know

I'm all old, retiredlike and put out to pasture...not current for decades....so I ponder this neat stuff, cool to see a video

To me it's like insider at the factory fellowship stuff, you know what I mean?

Like does anyone have the video of Boeing busting the wing on the 787 was it....loaded till it broke was the plan......actual wing went almost 90 friggin degrees before it snapped

originally posted by: BASSPLYR
a reply to: FredT

Not quite a wind tunnel but i got pacific gas and electric to take photos of me in high definition colored IR doing martial arts poses once. Turns out your ears and nose are much colder than the rest of your body.

Thats pretty cool!

a reply to: GBP/JPY

I saw footage of the wing bending test. Its hard to believe unless you see it with your own eyes. The wing bent like 60 degrees befor snapping. Its reassuring when on a flight with turbulance and you see the wing bouncing around.

Do they have footage of the tests on the rear set of wheels. Now that must look pretty awesome

originally posted by: BASSPLYR
a reply to: GBP/JPY

I saw footage of the wing bending test. Its hard to believe unless you see it with your own eyes. The wing bent like 60 degrees befor snapping. Its reassuring when on a flight with turbulance and you see the wing bouncing around.

ive seen the videos aswell. youd swear its practically at a 90 degree angle before it finally lets loose. amazing amount of kit the whole setup is that tugs on the wing aswell

originally posted by: Zaphod58
a reply to: FredT

I SO want to visit their wind tunnel.

Wind tunnels are so 20th century.
The video is computer output.

Solidworks had a plugin called Flow works about 15 years ago that did virtual fluid testing..Probably a lot better with the mathematics now..A mate was playing around with a Star Destroyer in a wind tunnel a while ago.

Its a shame they don't give more info about the simulation.
I think it must be direct numerical simulation (DNS) to require a supercomputer.
This bypasses using turbulence models so you can directly resolve the effects of turbulence by solving Navier-Stokes equations on a high resolution grid, which requires a huge amount of computation.

The current landing gear doesn't look very aerodynamic, it could definitely be redesigned to cause less drag.

originally posted by: Dr X
Its a shame they don't give more info about the simulation.
I think it must be direct numerical simulation (DNS) to require a supercomputer.
This bypasses using turbulence models so you can directly resolve the effects of turbulence by solving Navier-Stokes equations on a high resolution grid, which requires a huge amount of computation.

The current landing gear doesn't look very aerodynamic, it could definitely be redesigned to cause less drag.

For kanding, which is the only time the gear is down, drag is good. It allows the airvrft to slow down without severely increasing angle of attack, which is what causes an aerodynamic stall. So, when on approach, tou retard power somewhat - say to 75 to 85% power, drop the flaps to approach setting or 8 degrees or so, then drop the gear to slow down some more, and add a little power to establish the correct glide path and reduce engine spool up lag in the event of a missed approach or go around. then drop full flaps which usually automatically extends any leading edge devices. then pull power back to flight idle and pull the nose up some to flare and touch down. If all goes well, you can even use the aircraft again/

that's interesting, thanks.
I guess the other important thing is the vortices. The low pressure associated with them might draw the front of the plane down. Similar to the down-force that F1 cars use.

a reply to: F4guy
Cross wind landings is where Id be looking into.

This study is geared towards noise reduction as airports are coming under increasing pressure to cut down after hours air operations and the like. The write up indicates that the gear et al can make more noise than the engines on approach so they are trying to see what they can do to quiet things down.

originally posted by: Dr X
that's interesting, thanks.
I guess the other important thing is the vortices. The low pressure associated with them might draw the front of the plane down. Similar to the down-force that F1 cars use.

Actually, on most aircraft, dropping the gear causes a noticeable pitch up. An exception is the DC-3, which has enormously heavy landing gear which swings forward, causing a forward move of the center of gravity, resulting in a pitch down.

originally posted by: Blackfinger
a reply to: F4guy
Cross wind landings is where Id be looking into.

Why is that?