NASA developing quiet wing to reduce noise pollution at airports

NASA developing quiet wing to ...
The CRM-QHL flanked by sound baffles and acoustic sensors
The CRM-QHL flanked by sound baffles and acoustic sensors
View 2 Images
The CRM-QHL flanked by sound baffles and acoustic sensors
The CRM-QHL flanked by sound baffles and acoustic sensors
The CRM-QHL in the wind tunnel
The CRM-QHL in the wind tunnel

As part of its Advanced Air Transport Technology (AATT) Project, NASA is working on a new leading-edge wing design that aims to decrease aircraft noise while taking off and landing.

When someone mentions noise pollution by aircraft, often the first thing that comes to mind is the roar and whine of the jet engines that propel the vehicle through the sky, but the airframe and especially the wings can produce a lot of noise as well. This is due to the mind-bogglingly complex flow of air over the lifting and control surfaces, and is loudest when an aircraft is flying slowly through the denser air at low altitude.

Such noise is a problem on several levels. It's not only unpleasant and disruptive for people living in the vicinity, but it wastes energy that could be used to propel the craft. It's also expensive, because airports base their fees in part on the amount of noise an aircraft generates.

The CRM-QHL in the wind tunnel
The CRM-QHL in the wind tunnel

To better understand this phenomenon and find ways to mitigate it, NASA engineers completed subsonic wind tunnel testing in January 2021 on a one-tenth scale model of a new wing design called the Quiet-High-Lift version of the Common Research Model (CRM-QHL).

The test model consisted of a simplified fuselage cut in half and laid on its flat side on the floor of the wind tunnel. On the fuselage is mounted a detailed model of an aircraft wing, including operating slats and flaps, as well as a model engine and a retractable undercarriage. This allows the researchers to gather empirical data with which to assess the extremely complex computer models needed to simulate wing noise.

The idea is to modify wing components like the leading-edge slat and trailing-edge flaps to make them more efficient in terms of their aerodynamic, structural, and acoustic performance using shape-memory alloys. When the small-scale model tests are completed, the plan is to pass on to large-scale wind tunnel tests to develop the technology to the point where it can be adopted by the aerospace industry.

Source: NASA

For an article about a new leading edge there a remarquable lack of information on said leading edge.
First place to look IMO would be owls.
Spot on. We have reduced the amount of noise made by fans using the structure of an owls wing. They are the quietest bird in flight on the planet. If you want innovation look to nature.
I think the undercarriage noise is an order of magnitude higher than the slats or the Fowler flaps. When flying on these great planes, you can definitely hear and feel when the flaps are extended, and the vibration and roar from the undercarriage when extended is really significant. I would say at least 10 dB higher, which means it becomes the dominant noise source, drowning out the tiny noise increase of the slats.
Honestly, they are chasing shadows, in my view.
Expanded Viewpoint
Now I'm no ornithologist, or physicist or expert in aerodynamics to say if it's true or not, but many years ago I read that the reason why an owl's wings are so deadly silent, is because their feathers at the trailing edge are downy soft, and absorb sound waves, rather than transmit them.
Yes, Username, once again, we are enticed with a sexy sounding lead in to a story, which then falls flat on it's face with legs splayed upwards, champagne glass broken and bubbly spilled on the floor . Hardly sexy at all.

Nelson Hyde Chick
Catweazle, what makes owls wings quiet substantially increases drag, so to mimic an owl's wing would reduce speed and increase fuel consumption.
How about mandating a fix to the decades known A320 wing whistle from the fuel overpressure port? It's ear splitting and propagates for miles. Europe requires a fix, why not the US?
There is no doubt that an owl's wings are silent, but then again, so are the wings of many birds when they're gliding and not flapping. Furthermore, their speeds are no match for an airliner.
It's hard to believe that the noise generated by the aircraft's wings are as loud or even close to the noise of a jet engines or the blades of a turboprop. Still, any methods to reduce their noise is welcomed. When I hear a plane flying in the sky it seems obvious that the noise is coming mostly from the jets.