Beaver-inspried wetsuits could keep divers warm underwater
Larger marine animals like whales and eared seals have a natural layer of fat or blubber on their bodies that keep them warm and dry while diving. But small animals like beavers and sea otters have a dense layer of fur in place of the blubber that help them stay warmer in the water and enable them to survive the harsher conditions of the ocean.
MIT researchers believe that this approach could help humans in keeping warm underwater as well. So, they have fabricated a wetsuit that consists of fur-like, rubbery pelts and can replicate the mechanism as seen in beavers.
“People have known that these animals use their fur to trap air. But, given a piece of fur, they couldn’t have answered the question: Is this going to trap air or not? We have now quantified the design space and can say, ‘If you have this kind of hair density and length and are diving at these speeds, these designs will trap air, and these will not.’ Which is the information you need if you are going to design a wetsuit.” Co-auhtor Anette (Peko) Hosoi, a professor of mechanical engineering and associate head of the department at MIT said in a statement.
To make wetsuits actually work like beaver’s fur, researchers conducted experiments to understand the air-trapping effect like they designed fur like surfaces of various dimensions, plunge them into the water at varying speed and measured the air that is trapped in the fur during each dive.
Researchers found that the spacing of individual hair and the animal’s diving speed play an important role in determining how much air a surface could trap. Researchers then created a model that was close to being accurate. They placed a series of tubes and illustrated the flow of liquid within each tube and measured the pressure balance between the liquid and air layers. Thicker layer was closer to the surface and progressively thinned out with depth while denser fur that were dropped at higher speeds generally trapped more air within their hairs.
“Basically we found that the weight of the water is pushing air in, but the viscosity of the liquid is resisting flow (through the tubes),” explains Hosoi. “The water sticks to these hairs, which prevents water from penetrating all the way to their base.”