"Humpback whales are impressively agile swimmers—thanks in no small part to the rows of bumps, called tubercles, on the leading edges of their flippers. Tubercles generate swirling water formations, called vortices, which help the massive mammals maintain lift and delay stall, an aerodynamic phenomenon in which the flow of fluid over the top of the flipper becomes separated from the flow underneath, causing increased drag.
Previous research has shown that adding tubercle-like bumps to wind turbine blades could make the blades better able to harvest energy, especially at low speeds. Engineers have already applied the principle to industrial fans and continue to develop whale-inspired wind turbine technology. Now, researchers at the U.S. Naval Academy (USNA) have shown that adding bumps to underwater tidal turbines also improves their performance, too. In a laboratory experiment, the results of which they presented November 22 at the annual meeting of the American Physical Society’s Division of Fluid Dynamics, bumpy turbines produced significantly more energy at low speeds, when compared to a standard turbine with smooth-edged blades.
Ocean tides represent a large potential source of renewable, nonpolluting energy. But the tidal power industry has been slow to emerge, in large part due to technical challenges. One important obstacle facing engineers is the difficulty of designing turbines that do not stall in slow-moving water."
Bumpy humpback flippers inspire new tidal turbine design