A new understanding of flying snakes may lead to advances in technology
By Ben Coxworth
March 6, 2014
So first of all ... yes, flying snakes do exist. Disappointingly, though, they don't have scaly dragon-like wings. Instead, they're able to flatten out their bodies after launching themselves from tree branches, proceeding to glide through the air for up to 100 feet (30.5 m). Recently, scientists figured out why that technique works as well as it does. Their findings could have some major applications for us humans.
There are three species of flying snakes, all belonging to the genus Chrysopelea, and all being found in the forests of Southeast and South Asia. They rotate their ribs in order to flatten themselves, and make an undulating side-to-side motion (as snakes will do) while gliding.
Jake Socha, a biomechanics professor at Virginia Tech, used tubing to build physical models of the snakes, which his team tested in a wind tunnel. Based on his observations of the real animals, it was expected that the models would experience more aerodynamic lift as they increased their angle of attack (i.e: the degree to which their nose was raised relative to the oncoming air flow), culminating in a sudden stall and drop. Instead, the researchers noted "lift increasing up to an angle of 30 degrees, a sharp boost at an angle of 35 degrees, then a gentle decrease."
Why was this the case? That's where Lorena Barba, an associate professor of mechanical and aerospace engineering at Washington DC's The George Washington University, came into the picture.
Working with research assistant Anush Krishnan, she created a computer model of the "wing" section of a snake's body. Using that model in computational fluid dynamics simulations, she observed the same lift phenomenon that Prof. Socha noted, known as a lift enhancement mechanism. In her case, however, she was able to "zoom in" on the flight surfaces, to better see exactly what was going on.
It turns out that at certain glide angles, curves in the animals' bodies create small whirlwind-like vortices in the surrounding air, essentially sucking the snakes higher. Barba still isn't clear on the role played by the side-to-side motion, but plans on using a computer model of a complete snake body to find out. She hopes that her findings could be put to practical use.
"It’s not wild to think that our understanding of the fluid mechanics of this particular shape could lead us to, for example, design a different type of air flow that is ideal for energy harvesting, or a wind turbine – or who knows,” she said. "You find applications in unexpected places."
A paper on the flying snake research was recently published in the journal Physics of Fluids.
Source: The George Washington University