Robots may now move in ways that resemble those of animals, such as walking and swimming. Scientists are currently thinking of ways to create robots that resemble the gliding motion used by flying snakes.
Researchers from Virginia Tech and the University of Virginia investigated the lift-producing mechanism of flying snakes in Physics of Fluids, published by AIP Publishing. Flying snakes undulate as they descend from the tops of trees to the ground to evade predators or to move quickly and effectively. Snakes can glide for a long distance—up to 25 meters from a 15-meter tower—due to the undulation.
The researchers used data from high-speed footage of flying snakes to construct a computational model to explain how the undulations provide lift. The snake’s body’s cross-sectional shape, which resembles an extended frisbee or flying disc, is a crucial aspect of this concept.
To comprehend how the snake can glide so far, one must first understand its cross-sectional shape. When a frisbee is spun, it increases the air pressure underneath it and creates suction on top, which lifts the disc into the air. The snake undulates from side to side, producing low pressure above its back and high pressure beneath its belly, to help produce the same type of pressure difference over its body. The snake is raised as a result, enabling it to float through the air.
According to the author Haibo Dong of the University of Virginia, “the snake’s horizontal undulation forms a variety of important vortex formations, including leading edge vortices, LEV, and trailing edge vortices, TEV.” On the dorsal, or rear, surface of the snake’s body, the LEV’s formation and development are crucial for providing lift.
Near the head, the LEVs begin and move back along the body. The researchers discovered that the LEVs remain in place for longer periods of time before being shed along the snake’s body curves. These curves, which are crucial to comprehending the lift mechanism, are created during the undulation.
In order to identify which characteristics were crucial for producing glide, the group took into account a number of characteristics, including the angle of attack the snake forms with the incoming airflow and the frequency of its undulations. Flying snakes often undulate approximately 1-2 times per second in their native habitat. Unexpectedly, the researchers discovered that faster undulation lowers aerodynamic performance.
“The common pattern we observe is that when frequency rises, the vortex structure becomes unstable and some vortex tubes begin to spin.” “There is less lift as a result of the spinning vortex tubes tending to separate from the surface,” said Dong.
The researchers anticipate that their findings will contribute to a better understanding of gliding motion and to the development of gliding snake robots that are better designed.
