A West Chester University professor has developed a new wind turbine that draws inspiration from a blubbery source: the flippers of a humpback whale.

Those knobby flippers were long considered one of the oddities of the sea, found on no other earthly creature.

But after years of study, starting with a whale that washed up on a New Jersey beach, Frank Fish thinks he knows their secret. The bumps cause water to flow over the flippers more smoothly, giving the giant mammal the ability to swim tight circles around its prey.

What works in the ocean seems to work in air. Already a flipperlike prototype is generating energy on Canada's Prince Edward Island, with twin, bumpy-edged blades knifing through the air. And this summer, an industrial fan company plans to roll out its own whale-inspired model - moving the same amount of air with half the usual number of blades and thus a smaller, energy-saving motor.

Some scientists were sceptical at first, but the concept now has gotten support from independent researchers, most recently some Harvard engineers who wrote up their findings in the respected journal Physical Review Letters.

"There's definitely something going on with these bumps," said Ernst A van Nierop, the paper's lead author.

The saga starts with Fish, a tae kwon do black belt who breaks boards to demonstrate muscle control to his anatomy students.

Fish is a sort of modern-day cousin of the Wright brothers, in that he seeks inspiration from the animal kingdom. He's a professor of biology at West Chester, sharing his office with a small alligator named Wally, but a more specific term for him is functional morphologist.

Why are animals built the way they are? Which features - limbs, tails, noses - give them an edge in propulsion, conserving energy, avoiding predators?

Fish's research is born of pure scientific curiosity, his interest ranging from muskrats to alligators. But many want to use his insights for human technology, convinced that we can learn a few tricks from what nature has evolved over millions of years.

So now he is working with the military to develop submarine robots inspired by manta rays. And he's studying the nasal cavity of the shark, which might lead to developing an artificial nose.

The first of these animal-inspired ideas to reach fruition is the whale-flipper wind turbine.

Fish was visiting Boston about 25 years ago when he and his wife wandered into a gallery that featured sculptures of animals.

One was a small rendition of a humpback whale. Fish hadn't worked much with marine creatures at the time, but he was pretty sure the sculptor had made a mistake. There were bumps on the front edge of the mammal's flippers. Fish was sure they belonged on the rear edge.

The gallery owner overheard him making a derisive remark, and brought over a brochure with a photograph of the humpback. Indeed, the bumps were on the front.

"It just drove me insane," recalls Fish, now 55. "Because why should that be?"

Determined to find out, he put in a request for a flipper specimen

from the Smithsonian Institution. Museum officials finally called years later, around 1990, to tell him a dead humpback had washed ashore in New Jersey. He was welcome to come get a flipper at the Marine Mammal Stranding Center in Brigantine, but he had to cut it off.

He was told the whale was about 20 feet long. Knowing that a humpback's flippers are about one-third of its body length, Fish estimated that one of the flippers would measure 6 feet. A tight fit for his Mercury Lynx hatchback, but he could manage.

Then he got there and found the whale was closer to 30 feet, the flipper 10 feet. He had brought his Black & Decker crosscut saw with him, but it took hours to cut the flipper into three sections. Each piece weighed more than 100 pounds, and he watched his rear bumper sag more and more as he placed each piece in the trunk.

"I drove back in absolute fear that a New Jersey state trooper would stop me, having rotting body parts in black plastic bags," he says.

The pieces spent two years in the freezer. Fish couldn't get anyone to make a cast of the giant frozen pieces, so he couldn't make a model to study it.

Eventually, he and colleague Jan Battle cut the pieces into 1-inch sections - failing with a series of smaller saws until they used a butcher-quality model at the University of Pennsylvania's veterinary pathology lab.

As they had expected, they found the flipper's cross-section looked rather like that of a wing. But what were the bumps for?

One of the ways an airplane pilot generates lift is by increasing the wings' angle of attack. The front edge of the wing is tilted upward, deflecting the oncoming wind so that the wing rises. The phenomenon is the same as when you stick your hand out the window of a speeding car.

But if the angle is increased too much, the air rushing over the top of the wing becomes turbulent, tumbling over itself in undesirable eddies. The wing will stall.

Yet when models of the bumpy flippers were tested in a wind tunnel, Fish and his colleagues found something interesting. The flippers could be tilted at a higher angle before stall occurred.

The scientific literature had scant reference to the flipper bumps, called tubercles. Fish reasoned that because the whale's flippers remained effective at a high angle, the mammal was therefore able to manoeuvre in tight circles.

In fact, this is how it traps its prey, surrounding smaller fish in a "net" of bubbles that they are unwilling to cross.

In 2004, along with engineers from the US Naval Academy and Duke University, Fish published hard data: Whereas a smooth-edged flipper stalled at less than 12 degrees, the bumpy, "scalloped" version did not stall until it was tilted more than 16 degrees - an increase of nearly 40 percent.

Fish then partnered with Canadian entrepreneur Stephen Dewar to start WhalePower, a Toronto-based company that licenses the technology to manufacturers. They have since made airfoils that can be tilted even more before stalling, up to 30 degrees - though in the real world they wouldn't go that high, in part because of an unwelcome increase in the resistant force known as drag.

Exactly why the tubercles work is not fully understood; there may be more than one reason. Those who've studied the bumps agree that somehow they delay "separation" - the fateful turbulence that is associated with stall.

A key seems to be the difference in pressure between the air rushing over the tubercles and the air channelled through the "troughs" in between.

Last summer, a traditional wind turbine was modified with bumpy blades and is being tested by the Wind Energy Institute of Canada.

And Envira-North Systems, a maker of industrial fans in Seaforth, Ontario, plans to have a bumpy-bladed model on the market by the end of the summer.

"I was a sceptic at the beginning," said Stephan Gingras, the fan company's research and development manager. "I'm not a sceptic anymore."

It has all been a bit of a culture shock for Fish, who is more at home in the open world of academia than the more secretive realm of inventions and patents. Two decades ago, his only motivation was to figure out what the bumps were for.

"I sort of found something that's in plain sight," he says. "You can look at something again and again, and then you're seeing it differently."