Scientists have been studying the incredible agility displayed by humpback whales, and now researchers at Harvard believe that agility is due to tubercles – the odd grouping of bumps on the leading edge of the whale’s flipper. A Canadian company called WhalePower is now producing several designs for wind turbine blades and air circulation fans based simply on this study. Researchers believe that their findings could be applied to airplane wings and helicopter rotors in the future. This combination of biology and engineering is known as biomimetics, and many argue that it’s the key to making current technologies more efficient.
The secret to the tubercles success has been discovered in wind tunnels. The tubercles allow for the surface (wing, flipper, etc.) to achieve a higher angle of attack before stalling. Specifically, a tubercle-lined flipper has a 40% higher angle of attack compared to a smooth flipper. An article recently published in Nature goes further, saying the tubercles change the pressure distribution across the surface, causing different parts of the flipper to stall before others and delaying the inevitable stall. Stalling is similar to a car spinning its wheels in that all the power generated by the surface is lost.
What I found to be the most promising outcome of this research concerned the potential improvement in wind turbine blade design. Prototypes of the whale-inspired blades have shown that the tubercles double the performance of the blades at wind speeds of 17 mph. They have also been able to capture the same amount of energy out of 10 mph winds that older designs can only get out of 17 mph winds, making wind generation much more efficient and profitable. The new blades are advertised as being more stable, quiet, and durable than conventional blades. Some have withstood hurricane force winds. The first commercial applications are being made in ventilation fans. They are due on the market in Canada in late April.
Biomimetics and renewable energy sources sounds like a match made in heaven...literally.