New research led by the University of South Florida has uncovered one of the reasons jellyfish have come to be known as the “world’s most efficient swimmer.” Brad Gemmell, associate professor of integrative biology, found jellyfish produce two vortex rings, which are donut-shaped bodies of fluid underneath their translucent bodies, that spin in opposite directions. They appear as jellyfish squeeze and reopen throughout each swim cycle, providing a “ground effect” force as if they were to be pushing off the seafloor.
The “ground effect” is most widely understood on airport runways. During take-off, air squeezes between the airplane and ground, which builds pressure and a force that boosts performance. Gemmell’s experiments have shown that jellyfish can use their two vortex rings in place of the ground. The vortex rings resist each other, creating a “virtual wall” that provides a similar boost in performance compared to animals that swim near the bottom. Never before has it been proven that an animal can create this phenomenon away from a solid boundary.
“The fact that these simple animals have figured out how to achieve a ‘ground effect’ type boost in open water, away from any solid surfaces, has the potential to open up a range of new possibilities for engineered vehicles to take advantage of this phenomenon,” Gemmell said.University of South Florida (USF Innovation), “Jellyfish create a ‘virtual wall’ to enhance performance” at ScienceDaily
The paper is open access.
Either jellyfish are smarter than we think or there is design in nature.