Condor-Like Winglet Increases Wind Turbine Efficiency By 10%, Shows Study

Condor-Like Winglet Increases Wind Turbine Efficiency By 10%, Shows Study

A recent report published in the journal Energy has shown that a novel winglet, inspired by the condor’s wings can boost a turbine’s energy output by an average of 10%. This was done by the University of Alberta. Engineers at the Department of Mechanical Engineering at the University of Alberta looked to the Andean condor for answers on how to improve wind turbine efficiency. Wind turbine blades, like any aerodynamic design, strive to extract maximum power from moving air.

The Andean condor, native to the Andes mountain range in South America, is the largest flying bird on the planet. Its wingspan can reach a staggering 10 to 12 feet. Despite weighing up to 35 pounds, these birds of prey demonstrate extraordinary aerial prowess. They can effortlessly soar for up to 150 miles per day without flapping, due to their remarkably drag-reducing wing design.

The exercise highlighted that retrofitting wind turbines with bio-inspired winglets can enhance the power output, with an average increase in energy production by 10%. The boost in power production is attributed to the aerodynamic changes introduced by the winglet, not just an increase in the rotor’s swept area. Further, the presence of winglets modifies the vortex structures at the blade tips, reducing the rotational tendencies of the flow near the tip. The winglets improve wake recovery and have a positive effect on the recovery of velocity deficit, stated the report published in the journal Energy.

To improve the efficiency of the turbine there should be an increase in the lift-to-drag ratio, which can be achieved by reducing the total drag. The total drag is the sum of the form drag, friction drag, and induced drag. The induced drag is the direct consequence of the downwash created by the presence of the tip vortices. The pressure difference between the two sides of the wing causes the flow at the blade’s tip to curl towards the other side of the wing, leading to the generation of tip vortices. The presence of these vortices causes the flow in the neighboring region to move downward. The downward component of velocity induced by the tip vortices is known as the downwash, which leads to an increase in drag coefficient.

Most modern-day airplanes, from business jets to military planes, use winglets to minimize the effects of tip vortices. The addition of winglets to airplanes’ wings causes a reduction in the induced drag coefficient and increases the bending moments near the tip. Bio-inspired designs and biomimicry have been proven to be valuable assets and have shown great promise in various bio-fluid mechanics applications.

During the experiment, the force distribution on the blades showed that adding winglets leads to an overall increase in the load distribution along the span, increasing the axial loading by 8.5% in the extended winglet blade.

According to a report, on average, Boeing 737-800s benefit the most from winglets. They average a 6.69% increase in efficiency but depending on the route have a fuel savings distribution spanning from 4.6% to 10.5%. winglets can lower fuel consumption anywhere from 1% to 10%.