Shark skin inspires design for better drones, planes

Boston: Harvard scientists have developed a new structure inspired by shark skin that could improve the aerodynamic performance of planes, wind turbines, drones and cars. The study published in the Journal of the Royal Society Interface sheds light on a decadesold mystery about sharkskin. Sharks and airplanes are not actually all that different. Both are designed to efficiently move through fluid ( water and air), using the shape of their bodies to generate lift and decrease drag, researchers said. The difference is that sharks have about a 400 millionyear head start on the design process, they said. “The skin of sharks is covered by thousands and thousands of small scales, or denticles, which vary in shape and size around the body,” said George Lauder, professor at Harvard University in the US. “We know a lot about the structure of these denticles — which are very similar to human teeth — but the function has been debated,” said Lauder. Most research has focused on the drag reducing properties of denticles but Lauder and his team wondered if there was more to the story. “We asked, what if instead of mainly reducing drag, these particular shapes were actually better suited for increasing lift,” said Mehdi Saadat, a postdoctoral fellow at Harvard, who holds a joint appointment at the University of South Carolina. For inspiration, they turned to the shortfin mako, the fastest shark in the world. The mako's denticles have three raised ridges, like a trident. Using micro- CT scanning, the team imaged and modelled the denticles in three dimensions. Next, they 3D printed the shapes on the surface of a wing with a curved aerodynamic cross- section, known as an airfoil. “Airfoils are a primary component of all aerial devices,” said August Domel, a PhD student at Harvard. — PTI