Researchers have long looked to the shark for inspiration for improvements in fluid dynamics. The animals have been roaming the seas for 400 million years and have their very efficient movements to show for it.
In previous studies, scientists have looked to shark skin for ways to reduce drag in aircraft, but this latest research done by biologists and engineers from Harvard University and the University of South Carolina focuses on how the properties of shark skin can improve lift. This information could improve the efficiency of airplanes, drones and wind turbines.
The basis for this research is denticles, tiny scales that have three raised ridges like a trident, that cover different parts of a shark's body and vary in shape and size depending on where they're located. These structures have been shown to increase lift and decrease drag when a shark swims and could lend the same benefits to airfoils -- the aerodynamic cross section of an airplane wing (or wind turbine blade).
The researchers looked at a specific species of shark -- the shortfin mako -- famous for being the fastest shark alive. They performed micro CT scans the skin and then created 3D models of the denticles and printed them onto an airfoil. They then tested the airfoil in a water flow tank, using 20 different configurations of the structures.
The tests showed that the shapes significantly improved the lift to drag ratio -- by up to 323 percent -- compared to an airfoil without the denticle designs, acting as high-powered, but low-profile, vortex generators.
This discovery could lead to much more fuel efficient airplanes and wind turbines that can generate more electricity without increasing blade size.