Humpback whale flippers inspire Canadian design of highly efficient wind turbine blade

Whale Tubercles helping wind turbine efficiency Photo: biomimicry2016 -

Global sales in wind turbine market are expected to grow from EUR 64.5 billion in 2015 to EUR 66 billion in 2019

The 15 finalists for the European Inventor Award 2018, announced this week by the European Patent Office(EPO), have all made significant contributions to advancing technology, generating economic value and creating employment in Europe and throughout the world, according to a press release.

One team stands out: an American biologist, a US/Canadian aeronautical engineer and a Canadian inventor and entrepreneur, who looked to nature to develop quiet and efficient turbines, industrial fans and blowers.

The biomimetic turbine blade design is based on the “bumpy” flippers of humpback whales and can help wind farms produce up to 20% more power and increase airflow by up to 25% in industrial fans and blowers.

Turbine aerodynamic performance has been significantly improved and noise reduced thanks to the tubercle technology developed by biologist Frank Fish, aeronautical engineer Philip Watts and film-maker, inventor and entrepreneur Stephen W. Dewar. This team achieved its breakthrough after Fish discovered that tubercles – the small bumps on the leading edge of humpback whales’ flippers – reduce unwanted whirling masses of air called vortices, thereby reducing drag while simultaneously increasing lift.

The discovery challenged conventional aerodynamics wisdom, which had long held that the leading edge of propellers, blades and turbines should be as smooth as possible to limit air resistance. It turns out that these specially placed bumps can deliver a significant increase in performance. To transform this insight into blade designs for wind turbines, cooling fans and industrial blowers, the team set up the start-up WhalePower, which now licenses the technology to prospective manufacturers.

Societal benefit

Able to boost the energy production of wind farms by up to 20%, while producing less noise and requiring less maintenance, the technology holds tremendous potential for the wind power sector.

WhalePower’s tubercle technology concept was licensed to a German green energy producer which commissioned the German Aerospace Center to study model wind turbine blades equipped with tubercles in a wind tunnel. They found that noise was reduced by at least 2 decibels and material wear by 6 to 8%, and the lifetime of key components extended by 25% – the equivalent of three to six more years of use given the average 12 to 25-year lifetime of a wind turbine.

For fan and turbine applications that use, rather than produce, energy, tubercle blades can increase air circulation by up to a quarter while requiring less energy. A leading manufacturer tested a prototype fan for cooling computer graphics cards and found the design to be about 20% more efficient than the current market leader. This is a compelling proposition to the IT industry where fans and cooling consume around 10% of the total power in certain applications, such as servers.

Economic benefit

WhalePower operates as a virtual intellectual property firm, licensing its designs to other companies that wish to use the technology in their particular areas of expertise.

The company introduced the first tubercle-blade high-volume, low-speed (HVLS) fan to the market through its licensee Envira-North Systems. Called the Altra-Air, this industrial-scale fan is available in a range of sizes in 38 countries. It promises 20, 000 hours of maintenance-free operation while consuming as little energy as an average hairdrier, and circulates about 25% more air than similar, non-tubercle fans. A second HVLS fan manufacturer, Shanghai Fast Link, also sells HVLS fans with tubercles in China.

Global sales in the wind turbine market are expected to grow from EUR 64.5 billion in 2015 to EUR 66 billion in 2019. The global market for industrial and commercial fans and blowers, where WhalePower has its first licensed product, is forecast to be worth some EUR 8.5 billion by 2022.

Fish, a leading expert on the biomechanics of how animals swim, surmised that the saw blade-like edge on humpback whales’ fins could be a reason for the large mammals’ remarkable endurance and speed (they weigh some 30 metric tonnes). Fish’s early studies of the flippers suggested that the tubercle bumps improved lift.

Fish wrote a research paper confirming his findings that captured Watts’ attention. The two teamed up to investigate the phenomenon more closely and to see if it might have practical applications. A typical aerofoil, they found, actually has to fight against the turbulent airflow it creates at its own tip. This results in vortices (whirling masses of air) that reduce efficiency and create extra noise.

Joined by Dewar, the team set up WhalePower to develop, patent and market their new blade design. By incorporating tubercle-inspired bumps, which they rounded and streamlined for maximum aerodynamic and fluid dynamic effects, they were able to increase the maximum lift of a wing while softening stall over what is termed the angle of attack by up to 40%. The net result was an efficiency gain of roughly 20% when using a blade with a tubercle-fitted front edge on a wind turbine. The more efficient leading-edge design could operate at a greater pitch (the angle to oncoming wind) and still continue to produce power in less windy conditions.

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