The scales of sharks might just serve as a key inspiration shape for the new generation of planes, drones, wind turbines and other aerodynamic machines. US engineers are already busy working on them.
Engineers and evolutionary biologists from Harvard and South Caroline University have demonstrated a new bio-inspired structure that could improve the aerodynamic performance of aircraft, wind turbines, drones and cars. It is inspired by the skin of a shark.
"The skin of sharks is covered with thousands of tiny tooth-like scales (denticles), which vary in shape and size at each spot of the body," says George Lauder, the co-author of the research into the structure. "We know a lot about the structure of these skin teeth - which resemble human teeth in many ways - but their function has been much debated."
Bearing surfaces
Most research has focused on how these denticles reduce drag, but the team instead looked at whether they could also increase lift. They used micro-CT scans to take images of the denticles in three dimensions and then 3D-printed them onto the surface of a support surface.
"Carrier wings are a primary component of all antenna devices," said August Domel, one of the researchers. "We wanted to test these structures on carrier surfaces as a way to measure their effect on lift and drag for applications in the design of various antenna devices such as drones, aircraft and wind turbines. "
The researchers tested 20 different configurations of denticle sizes, rows and row positions on support surfaces in a water flow tank. They found that, in addition to reducing drag, the denticle-shaped structures significantly increased lift and acted as high-powered, low-profile vortex generators.
More aerodynamics
Vortex generators are used in cars and aircraft to change the airflow over a moving object and make it more aerodynamic. "These shark-inspired eddy current generators achieve an improvement in lift-to-drag ratio of up to 323 per cent compared to a wing profile without vortex generators," Domel said. "With these proof-of-concept designs, we have demonstrated that these bio-inspired vortex generators have the potential to outperform traditional designs."
Lauder added: "This research not only outlines a new shape for vortex generators, but also offers insight into the role of complex and potentially multifunctional shark denticles."
By: Kelly Bakker
Source: Imeche
