/sci/ - Science & Math

Hi.
I'm not a scientist or engineer.
I've noticed modern plane engines seem to have teeth on the back side.
I did some googling and it seems it has been implemented to make engines less noisy. There doesn't seem to be a technical explanation online. The only answer as to how it works is "it changes the nature of the produced turbulence".
My questions are:
>1) Is there a resource I can consult to better understand how it works? It would be neat if somebody without a degree could understand it, but I guess that will probably not be the case. Does it maybe work by creating a group of small vortices that somewhat cancel each other rather than one big vortex?
>2) Could this technology be applied to the end of other tubes where gases of different speeds meet? Examples: exhaust pipes of internal combustion engines, muzzles of guns. Why or why not?