Some photos/diagrams would have been nice...

The problem is not the wing dear. You are taking aerodynamics all wrong . When you start pumping air in a medium where the air is steady the fast moving air and the motionless air collide its like a "air clap" that noise we here. Its technically a speaker the wind tunnel. To make the wind tunnel silent you need to pull the equal amount of air outside of the tunnel to make it less noisy. Better use gigantic noise cancellation speakers after the fan.

The secret of the silence of the owl's flight is not a special structure of the owl's feather, but the lower specific (weight per area) load of the owl's wing, relative to other birds. Attaching sound-supressing or vortex-supressing structures to the trailing edge of a turbine blade might help decreasing noise, but it has nothing to do with the owl's feathers.

There is some prior art here .... And this is already a Commercial Off the Shelf (COTS) item. In 2009 Stefan Oerlemans wrote a thesis on this titled Detection of aeroacoustic sound sources on aircraft and wind turbines. He later went on to do more research on this at the Netherlands Aerospace Center. Since he moved to Siemens they have now incorporated this feature in their windturbines, see https://www.siemens.com/press/PR2016090418WPEN

Has it occurred to anyone yet that this technique could be applied to airplane and boat propellers, wings, that sort of thing? If not, I take full credit. (-:

It stuns me that you would post stuff on wind engines and never once require the data on % efficiency.
N E V E R O N C E !!!!
You must not be real engineers but play toy versions who are simply hackers!
Bill Dickens

I'm more familiar with smaller wind turbines, but the vast majority of the noise created by wind turbines is in the -power train-, not the blades. Sure, quieter blades help, but let's lower the noise from the noisemaker, not the whup-whups.

@Imran: nothing is "pumping air" here. These are wind turbines; the entire air mass is moving past them, there is no shear layer "where the moving air and motionless air collide". The shear layer is at the surface of the blade, and directly downstream of it where the upper and lower streams recombine. And those places are exactly where they place the finlets, to smooth out air vibrations due to the shear.

Island Architect, I am sorry to hear that you are stunned, but this article concerns the noise of turbines, not the performance, and the performance is not affected at any rate as the noise was reduced by as "much as 10 decibels without affecting aerodynamic performance."

I've only seen a couple of wind turbines. From what I've seen the loudest noise they make is when their blades pass the tower with the classic low frequency "whumph" that travels for miles. Changing that interaction would be better if efforts were to be expended in just one place. A more aerodynamic shape for the tower/movable cowling would go a ways to reducing the air pressures at that point.