Wind turbine efficiency can be improved by increasing the lift-to-drag ratio through reducing the total drag stemming from downwash created by the presence of tip vortices. Taking a cue from the wings of the Andean and California condors, wind turbine blade tip retrofits were designed to decrease total drag and enhance wind system performance. Condors can glide and cover distances as large as 150 miles in a day without flapping their wings, taking a circuitous route comparable to the aerodynamics of a wind turbine.

As most modern airplanes use winglets to minimize the effects of tip vortices and reduce drag, transferring this technology to wind turbine blades could offer the same benefit. A bio-inspired winglet engineered by Canadian industrial design firm Biome Renewables was evaluated by University of Alberta, Canada, researchers for this application.

Computer simulations evaluated the effects of adding the 17.6 ft (5.35 m) long winglets, designed to be retrofitted to a wind turbine’s blade wingtip after production, to a 10 MW turbine. The analysis indicated that the condor-inspired addition exerted a great impact on vortex structures and reduced rotational tendencies of the flow at the vicinity of the tip.

The bio-inspired winglet (all dimensions are in meters). Source: Energy 292 (2024) bio-inspired winglet (all dimensions are in meters). Source: Energy 292 (2024)

The winglet increased the pressure difference between the suction surface and pressure surface along the blade’s span, which in turn increased the turbine’s torque and power production. An average energy production increase of 10% was attributed to the aerodynamic changes caused by the winglet and not just an increase in the blade’s swept area.

A paper detailing this avian-influenced wind turbine modifier is published in the journal Energy.

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