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Dr. Timothy Wei of University of Nebraska-Lincoln is studying the swimming efficiency of marine life. The research has several applications including in athletics and a potential use in the military. Brandon McDermott of NET News talked with Dr. Wei about his findings.
Brandon McDermott, NET News: Your research here focuses on marine life which can swim fast -- why focus on this and what was the goal?
Figure shows digital particle image velocimetry vector field with the flow generated by Megan Jendrick's (a participant in the study) breaststroke kick. Note the dark blue vectors pointing away from the bottom of her right foot. (Courtesy Tim Wei)
Dr. Timothy Wei, University of Nebraska-Lincoln : Well I think outside of the sort of the natural ‘coolness’ factor of being able to do it, there's a number of applications really – we’re familiar with drones in unmanned air vehicles – there's an intrusive parallel push in underwater.
So unmanned underwater vehicles. How do animals swim and can we develop engineering systems that mimic that? It's called biomimetics.
McDermott: So part of this research focuses on trying to engineer better systems that can swim underwater, but also we're trying to understand how humans can possibly swim faster as well, correct?
Dr. Wei: There's two elements to that – from a pure biological perspective if you just want to know how the human body or how animals do what they do. So there is an interest in humans swimming in that context or dolphins swimming for that matter in that context.
I think really the engineering is -- I don't know if it's so much humans – but it would be more really the high performance sports is a natural application for the human swimming.
McDermott: If we could talk a little bit about that, the evolution within athletics to focus on the science behind what's happening instead of the traditional way of looking at things, for lack of a better term the ‘X's and O's.”
A drawing of the force balance used to measure forces generated by swimmers. (Courtesy Tim Wei)
Dr. Wei: I’ll quote a guy name Russell Mark who was the technology person for USA Swimming and he made a comment to me a number of years ago and he said, "Basically, the sport has evolved to a point where we have two choices. We can either go to drugs or we can go to science and we obviously can't do drugs," so I think this is true in a lot of sports -- traditionally what you've done is just repetition over and over and over and over again. If you're repeating the right things that's good. If you're repeating the wrong things you end up with a lot of injury. There was an understanding that they were actually losing a lot of world class athletes because they were overtraining them and injuring them and they were not able to actually perform – they never reach their potential. So now there is actually a real focus on the science of sport.
McDermott: You also look at dolphins. What were you able to find about how they're able to reach such high speeds?
Dr. Wei: One of the measurements that we did, we basically used fluid mechanics and the science of fluids and we found that well, surprise, surprise that the dolphin actually has the power to go as fast as he did.
Time traces of swimming speeds, acceleration and rate of work associated with dolphin kicking for (a) Ariana Kukors and (b) a club swimmer, Lauren. (participants in the study). Note the shape of the world record holder’s energetics. (Courtesy Tim Wei)
But in between those two points there was a time when the thought was that the dolphin in fact did not have the muscle mass to go as fast as he could – so there must be something special about dolphin skin that makes it go fast and that's called compliant coatings. Actually this was during the Cold War, both the Russian Navy and the U.S. Navy spent millions of dollars studying complying coatings trying to figure out what was that special thing about dolphin skin that allowed them to go fast. What we find out is well surprise, surprise again dolphins actually go as fast as they do.
McDermott: How does this have say a military application?
Dr. Wei: The Navy actually has used animals in the past for various things, one of the things the dolphins do is – my understanding is – they have packs on their backs and they actually are sort of underwater couriers. If you can develop an engineering system that can do that, you don't actually have to be using animals to do these things. There are elements of stealth involved. If you have an engineered system that is mimicking the behavior of a marine animal, it's far less noticeable even if you do detect it. So the military is actually interested in just the same sort of thing as in the air – sort of drones and stealth for delivery of systems for surveillance.