Aircraft

Shark skin study promises lift in airplane and turbine design

Shark skin study promises lift...
In a new study, researchers turned to shark scales in an attempt to  improve the aerodynamic performance of planes, drones and wind turbines
In a new study, researchers turned to shark scales in an attempt to  improve the aerodynamic performance of planes, drones and wind turbines
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In a new study, researchers turned to shark scales in an attempt to  improve the aerodynamic performance of planes, drones and wind turbines
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In a new study, researchers turned to shark scales in an attempt to  improve the aerodynamic performance of planes, drones and wind turbines
Denticles of the shortfin mako shark from an environmental scanning electron microscope (ESEM) 
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Denticles of the shortfin mako shark from an environmental scanning electron microscope (ESEM) 
Denticles from the shortfin mako shark (a), the shortfin mako denticle parametric 3D model (b), the shortfin mako shark denticles were arranged in a wide variety of configurations on the aerofoil (c and d)
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Denticles from the shortfin mako shark (a), the shortfin mako denticle parametric 3D model (b), the shortfin mako shark denticles were arranged in a wide variety of configurations on the aerofoil (c and d)

Sharks have been around since before dinosaurs roamed the earth, which has given them plenty of time to perfect the art of aerodynamics. It's no surprise then that sharks, like whales, can teach us a thing or two about more efficiently moving through both water and air. A team of biologists and engineers from Harvard University and the University of South Carolina have taken a fresh look shark scales in the hope of making drones, planes and wind turbines more efficient.

Shark skin is covered in denticles, thousands of small scales, varying in shape and size for different parts of its body. Sharks use the shape of their bodies to increase lift and decrease drag as they move through water, and airplanes do the same thing to move through the air, making the fish ideal for research into airfoils – the aerodynamic cross-section of a plane wing.

"We know a lot about the structure of these denticles – which are very similar to human teeth – but the function has been debated," says George Lauder, co-author of the research.

Most research on shark scales has looked at how they affect drag, but Launder and his team instead concentrated on lift.

Denticles of the shortfin mako shark from an environmental scanning electron microscope (ESEM) 
Denticles of the shortfin mako shark from an environmental scanning electron microscope (ESEM) 

Specifically, the researchers looked at the shortfin mako, the fastest shark in the ocean, using micro CT scanning on the shapes of its denticles, which have three raised ridges, to model and print them in 3-D. They printed the shapes onto an airfoil, testing it from inside a water flow tank using 20 different arrangements of denticle sizes, rows and row positions. They found that by acting as high-powered, low-profile vortex generators, the denticles on the airfoil significantly increased lift.

"These shark-inspired vortex generators achieve lift-to-drag ratio improvements of up to 323 percent compared to an airfoil without vortex generators," says August Domel, co-first author of the paper. "With these proof of concept designs, we've demonstrated that these bioinspired vortex generators have the potential to outperform traditional designs."

Denticles from the shortfin mako shark (a), the shortfin mako denticle parametric 3D model (b), the shortfin mako shark denticles were arranged in a wide variety of configurations on the aerofoil (c and d)
Denticles from the shortfin mako shark (a), the shortfin mako denticle parametric 3D model (b), the shortfin mako shark denticles were arranged in a wide variety of configurations on the aerofoil (c and d)

"The results open new avenues for improved, bioinspired aerodynamic designs," says Katia Bertoldi, William and Ami Kuan Danoff, who each co-authored the study.

The team's research was published in the Journal of the Royal Society Interface.

Source: Harvard John A. Paulson School of Engineering and Applied Sciences

4 comments
Martin Hone
Vortex Generators have been proven to improve the performance of aircraft wings by re-attaching the airflow, so I guess the only difference here is that the shark inspired ones have an organic shape that may well be better than the single fin ones now in use. I look forward to trying them out if and when they reach the market.
Bruce H. Anderson
Adding to Martin Hone's remarks, some automobiles and long-haul trucks use stick-on vortex generators as well. While this new bio-inspired design may be an improvement, they might be a little difficult to clean around with those pointy ends. It would be nice if some of this research found its way to trailers by being incorporated into the leading and trailing edges, perhaps as a hydroformed piece instead of just an extrusion.
Al Nonamus
Maybe the shark uses these denticles to increase drag for maneuvering?
MarcJackson
Incorporating this research into new vehicle designs. Motorcycles having many opportunities where improving aerodynamics from the front wheel as bikes having catastrophic aerodynamics the fork tubes destroying flow potential out from front wheel making it's wheel wake far worse whereas cleaning up and flow turning this area into a positive.