In humankind’s quest to travel farther and faster, we apparently neglected to consider one pivotal question — how would Nature do it?

The thought occurred to biology Professor Jack Costello, Providence College, and his colleagues, upon discovering that a jellyfish robot swam significantly faster when the part of the body that propelled it was flexible.

That realization led the scientists to wonder how much the flexible margin should be. And, from a design standpoint, how would you incorporate the benefit of flexibility to enhance propulsion?

“When we looked at the literature, we found a lot of work, very nice work, but it makes all kinds of assumptions,” said Costello, a Rhode Island NSF EPSCoR researcher. “One alternative was too look at nature and see if there were any common features of natural propulsion. No one had really looked to natural examples to see what the common patterns were.”

The study team included fellow EPSCoR researcher Associate Professor Sean Colin, environmental science, Roger Williams University, and Professor John O. Dabiri, School of Engineering, Stanford University. In addition, several students from PC and RWU worked on the study during their undergraduate years. Their findings were published in Nature Communications  Feb. 18, 2014.

 “If all of these animals are doing the same basic motions in order to swim or fly, it suggests that there are some important constraints. And, understanding those constraints can help us better understand how we can design vehicles to swim or fly.”

The scientists confined the scope of their study to the steady state, or regular motion, as opposed to takeoff or landing. What they found was that once moving regularly, whether through water or air, be it fish or bird, or marine swimming snail, the margins or tips of animal propulsors tended to bend to the same degree.

Manmade propulsive devices typically are rigid; yet, natural propulsors have evolved along a substantially different course, which provides an entirely new perspective. For some reason, despite all of the rigidity found in nature — bones, shells, etc. — evolution went flexible for propulsion.

“Can we achieve that?” asked Costello. “As biologists, it’s very interesting to us and helps us understand animals. And, in this case, understanding animals probably has a very substantial engineering application.”

Both the study and the experience proved meaningful for everyone involved — the students, the biologists and the engineers. And ultimately, as is the case with scientific research, society will benefit as well.

Colin said the U.S. Navy, in particular, puts a lot of resources into this type of research and provided funding for the study.

He noted, “If all of these animals are doing the same basic motions in order to swim or fly, it suggests that there are some important constraints. And, understanding those constraints can help us better understand how we can design vehicles to swim or fly.”

Costello said if it were not for the engineers, he would not have been trying to answer the question about propulsion and flexibility in nature. Likewise, he added, the engineers were eager to learn from the biologists.

“Performance characteristics of animals are off the charts in many areas compared to designs that we currently have for human vehicles,” Costello said. “There is the potential to learn very important lessons from animals and how they operate.”

The multiple discipline approach is essential, he added, if scientists are going to unravel mysteries and solve complex problems.

Said Colin: “We can learn a lot from the world around us, and apply that knowledge to human engineered vehicles. Hopefully, these observations can improve and innovate designs.”

Story by Amy Dunkle