Noiseless Flight Coming Soon?
Well not completely noiseless to be sure. For now, that sort of thing will remain within the realm of science fiction. After all, the jet turbines that propel today’s aircraft are by nature rather noisy affairs. On the other hand, the noise that originates from the actual aeronautic design can be noticeably improved with some rather innovative findings that are about to be published in the American Institute of Aeronautics and Astronautics as well as the Journal of Sound and Vibration.
This upcoming papers outline startling new findings based from researchers at Lehigh University, Virginia Tech, Florida Atlantic University as well as the University of Cambridge. Get this: the researchers have analyzed the somewhat unusual biological structure that makes up the wings of owls. Yes, owls. As you probably know, owls have the unique ability to fly noiselessly.
It turns out that owls are able to achieve this noiseless flight due to the presence of what is best referred to as a velvety down found along the owl wing’s upper surface. For the record, this down is comprised of tiny hairs that are arranged in a particular manner. The hairs start out perpendicular to the feather surface but then bend over in the direction of flow. The end result is an interlocking canopy of sorts barbs at the top end that binds the hairs together.
Once the researchers determined that the presence of this down canopy mitigated any noise from the owl’s flight, they set about trying to replicate the effect in the laboratory. The end result the researchers arrived at is a unidirectional canopy. After employing state of the art 3-D printing manufacturing technology, the researchers created a plastic attachment that consists of “finlets” that can be attached to existing airfoil structures (think aircraft wings). Note that the researchers proved the efficacy of this noise reduction technique in the Virgina Tech Wall-Jet Wind Tunnel.
So what does all of this mean at the end of the day? Consider that these researchers have identified a innovative noise reduction technology that can be used in quite a number of applications. From cutting edge new aircraft designs to new quieter autos, buses and trains. In short, this new research can and does significantly reduce the effects of what is referred to as “trailing edge noise”, that is noise due to the effects of air as it flows over and around the back end of a structure.