What makes flying snakes such gifted gliders?
Animal flight behavior is an exciting frontier for engineers to both apply knowledge of aerodynamics and to learn from nature's solutions to operating in the air. Flying snakes are particularly intriguing to researchers because they lack wings or any other features that remotely resemble flight apparatus.
Before you envision flying snakes raining down from the sky, the ones involved in this study are small—about 1 meter in length and the width of your thumb—and live in the lowland tropical forests of Asia and Southeast Asia.
Virginia Tech Assistant Professor Jake Socha, renowned for his work with flying snakes, recently teamed with Boston University and George Washington University researchers to explore snakes' lift and wakes using computer simulations. They describe their work in the journal Physics of Fluids.
Previously, experiments in a wind tunnel had returned an unexpected finding: the snake's shape is not only good at generating a force of lift, but it also gets an extra boost of lift when facing the air flow at a certain angle.
"After experiments uncovered this, we decided to use computer simulations to try to explain it," says Lorena Barba, associate professor of mechanical and aerospace engineering at the George Washington University.
So much of the aerodynamics of animal flight—especially that of flying snakes—remain a mystery. Scale is important, but also the manner in which flight is achieved.
Whirls of wind can be particularly useful: these little vortices "can give flying snakes an extra lift," notes Barba. "The shape of the snakes in flight—which is a flattened version of its shape at rest—gets help from little vortices around it."
Next, the researchers would like to include more elements of the snake's real gliding conditions into their computer simulations, such as its full body forming an S-shape, rather than working with just a section.