Washington, Jan. 30: Researchers have claimed that the snakes flex their ribs as they launch to stretch and flatten the body to change their profile from a circle into an arched semi-circle, somewhat like a UFO.
To get to grips with the aerodynamic forces generated by the snake’s body, Jake Socha and his colleagues, Daniel Holden, Nicholas Cardwell and Pavlos Vlachos, used a 3D printer to produce a rod with the same UFO cross-section as the snake’s body before placing it across a tank filled with water that flowed over the snake-shaped bar.
Socha explained that although water is much denser and stickier than air, air conditions experienced as the snakes fly by flowing the water over the model at a specific range of speeds can be recreated.
Tilting the snake model at angles (of attack) ranging from -10 to 60deg as the water flowed over it at speeds ranging from 20 to 50cm/s, the team measured the lift and drag forces pulling on the model and saw that at most angles the animal’s unusual body shape generated sufficient lift to account for some of the snake’s impressive gliding performance.
But when the team tilted the model at 35deg, there was a massive spike in the lift generated by water flowing at higher speeds. More surprisingly, when the model was held level with the flow, instead of generating upward lift, the fluid pushed the rod down.
And when the team visualised the turbulent water flowing around the model with microscopic reflective beads, they could clearly see a spinning vortex sitting beneath the untilted snake shape, sucking it down: which may not be that crazy, according to Socha.
The study has been published in the Journal of Experimental Biology. (ANI)