The whale-inspired secret to better wind turbines

Posted: April 21, 2025

It was the early 1980s. Frank E. Fish, a West Chester University of Pennsylvania marine biologist, was strolling down a street in Boston when an animal art shop caught his attention. At the center of the shop was a pedestal with a scale model of a humpback whale.

The whale's flippers had bumpy, irregular edges, an unexpected feature, Fish thought. Conventional aerodynamic theories would suggest that smooth leading edges would provide the most optimal performance. Airplanes have a straight leading edge. Fans do too. What role could these curious bumps on humpback whales' flippers be playing? He wondered.

This question got Fish thinking. Little did he know that his observation could eventually drastically improve turbine blades' efficiency.

How humpback whale flippers inspired energy innovation

Despite weighing up to 36 tonnes, humpback whales are incredibly agile. They glide and maneuver their large bodies elegantly in the water as they travel up to 16000 km each year, achieving short speed bursts of roughly 25 km/h.

Since his encounter with the tiny reproduction of the animal, Fish was committed to finding out if the rugged shape of humpback whales' flippers had anything to do with the mammal's agility.

"The humpback whale actively maneuvers to capture prey, and the tubercles [the irregular bumps on the flippers] along with their long fins are important. Tubercles passively modify the flow over their wing-like flippers to give them greater lift and reduced drag," Fish explained in an interview with the European Patent Office in 2018.

A few years later, Fish examined the flipper of a stranded humpback and later built a computer model of it with help from an aeronautical engineer with a love for the ocean named Phil Watts.

The pair found that the tubercles on humpback whale flippers keep fluid flowing close to the surface of the flipper. When a wing—like a flipper, airplane wing, or fan blade—has too sharp an angle relative to the direction it's traveling through a fluid, the flow of fluid across the wing becomes turbulent, removing the low-pressure zone that causes lift and causing the wing to go into what's called a "stall."

Fish and Watts discovered that the whales’ tubercles allow whale flippers to turn at much sharper angles to their direction of travel before going into a stall. The airfoils they’ve produced inspired by the whales’ flippers don’t stall until they turn a full 31 degrees into the wind—a larger angle than any design previously created.

Moreover, when wings lose lift and stall, they usually do so violently, sometimes damaging the machines they're attached to. Wings with tubercles stall gradually, however, acting as passive-flow control devices that delay stall, enabling tighter turns. Tubercles create vortices that redistribute pressure along the flipper, preventing sudden flow separation- the point where the fluid (in this case, water) flowing over a surface (like the whale's flipper or a wing) detaches from that surface. Instead of smoothly following the contour of the object, the flow becomes turbulent and breaks away. This typically leads to a significant decrease in lift and an increase in drag, often causing a stall.

The vortices keep the water flowing smoothly over the flipper, even when the whale is turning sharply. As the flow of water is channeled into the scalloped valleys between tubercles, lift increases while drag decreases.

Without these tubercles, the flipper would stall, meaning the water would start to separate and create turbulence, which would make it harder for the whale to turn. This mechanism is analogous to how a car with proper traction can curve while a car on ice would skid tangentially. If you try to turn on the ice, your tires lose grip, and instead of following the curve, the vehicle will slide straight off in the direction it was going. But if you're on a regular road with good traction, your tires grip the road, and you can turn smoothly.

Watts, wondered: Could tubercles have a technological application?

From ocean to air: Engineering the future of wind turbines

Fish and Watts hypothesized that if tubercles improved movement in the water, they could also enhance aerodynamic performance in the air when applied to turbine and propeller blades.

They conducted fluid dynamic simulations on wings with and without tubercles, confirming that these bumps increased lift while simultaneously reducing drag.

Then, they refined the tubercle-inspired design, rounding and streamlining the bumps for maximum aerodynamic efficiency. Their tests demonstrated that incorporating tubercles could increase the maximum lift of a wing while delaying stall at high angles of attack (when the wing is tilted significantly relative to the oncoming airflow) by up to 40%. When applied to wind turbines, this translated to an efficiency gain of roughly 20%. These encouraging results led the duo to take their innovation a step further, co-founding WhalePower alongside Canadian journalist and entrepreneur Stephen Dewar in 2005.

Later, a German green energy producer licensed WhalePower's tubercle technology and commissioned the German Aerospace Center to conduct wind tunnel tests on model wind turbine blades featuring tubercles. The analysis revealed a noise reduction of at least 2 decibels. It also found a 6–8% decrease in material wear and a 25% extension in the lifespan of key components, which translated to an additional 3 to 6 years of use for turbines with an average lifespan of 12 to 25 years.

Tubercle blade applications in industry

While large-scale adoption in wind farms is still progressing, the technology has been integrated into several industrial applications. Industries that rely on fluid movement, such as those using industrial fans, blowers, pumps, mixers, and heating, ventilation, and air conditioning (HVAC) systems, can hugely benefit from tubercle-inspired designs. These are steel mills, foundries, chemical processing plants, food and beverage production facilities, paper and pulp mills, cement plants, you name it. There probably isn't one industry that does not use any fluid-moving system.

Improved fan efficiency can translate into significant energy savings, reduced operating costs, and a smaller carbon footprint. Lower noise levels can contribute to a better working environment.

As Phish put it, "From animals, we can learn so much—we just have to look carefully.”

Watts added, "Tubercles are a technology for the future. They'll allow us to create a sustainable planet and allow future generations to thrive."