GW Research Spring 2014 Edition

Flying Snakes Soar with Aid from Vortices

Flying snake
Chrysopelea ornata, one species of flying snake (Photo:
May 01, 2014

They slither, they sneak, they hiss, they ... fly?

Despite their wingless bodies, some snake species in the lowland tropical forests of Southeast and South Asia can glide—the animal kingdom’s only gliders to manage without appendages. They push off from tree branches, rotating their ribs to flatten their bodies and making side-to-side movements, soaring as far as 100 feet. One species is even known to turn in midair.

So how do they do it?

Lorena Barba, an associate professor of mechanical and aerospace engineering, led a team that built a two-dimensional computer model of a cross section of a snake in order to explore the fluid dynamics at work.

The study, conducted at Boston University and published online in March in the journal Physics of Fluids, confirms the findings of earlier physical experiments by team member Jake Socha, a biomechanics professor at Virginia Tech. But while that research suggested the snakes’ bodies generate quite a bit of lift, the computational study allowed the team to explore the forces behind it.

What they found was that small vortices, or whirlwinds, generated around the snake offer a boost in the form of upward suction. Next the team hopes to construct a 3-D model to investigate why snakes wiggle in the air.

“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 airflow that is ideal for energy harvesting or a wind turbine—or who knows,” Dr. Barba says. “You find applications in unexpected places." Lauren Ingeno