If the average person was asked to think of ways that future airplanes could be improved, “making them more fish-like” probably isn’t going to be among the top suggestions. But if researchers from City, University of London are correct, this could be one of the best decisions aircraft manufacturers could make.
In a new study, involving researchers from City and Germany’s University of Stuttgart, investigators set out to explore how fish-inspired scales could be used to improve the aerodynamics of aircraft by reducing drag. This, in turn, would mean faster aircraft speeds and less fuel consumption.
“We investigated how the surface of fish, with patterns of overlapping scales, [are used as] a means of reducing the drag of the fish body,” Professor Christoph Bruecker, City’s Royal Academy of Engineering Research Chair in Nature-Inspired Sensing and Flow Control for Sustainable Transport, told Digital Trends. “The scales seemingly reduce the friction drag, proven by detailed flow measurements [taken using] biomimetic scales.”
Experiments carried out by the researchers involved a special laminar water tunnel at the University of Stuttgart that was used to test the City hypothesis by comparing the drag on both a smooth flat plate and a flat plate covered in fake scales. (Such experiments would, Bruecker pointed out, be difficult to perform using real fish.) The idea is that the fish-scale array produces a zigzag motion of fluid in overlapping regions of the animal’s surface, which reduces skin friction drag by upward of 25 percent.
Unless something has gone slightly wrong, planes aren’t usually traveling in water, of course. But similar effects — involving the “physical principle of streaky flow generation” through overlapping scales — could also make the wings of aircraft more aerodynamic in flight. It may also have possible application in the design of future wind turbines.
Bruecker said that the technology to produce such biomimetic scales, perhaps using microlaser patterning, is already in existence. He said that the researchers next plan to investigate how large these scales might need to be in order to create the appropriate beneficial effect.
Now it’s time to mullet over
If you’re hoping for future airplanes that look like giant fish, you might be a bit disappointed. Bruecker suggested that the overlapping scales could be so small that they would barely be visible with the naked eye.
As to whether this research will be taken up by manufacturers, it was sponsored in part by BAE Systems, the defense and aerospace company that has previously supported some innovative projects such as energy-scattering deflector shields and military drones “grown” using chemicals.
“There is clearly interest in using such microstructured surfaces in aerodynamic applications, especially in the recent developments or laminar aerofoil technologies,” Bruecker said.
Other researchers on the project included City’s Muthukumar Muthuramalingam and Dominik Puckert, and Ulrich Rist from the University of Stuttgart.
A paper describing the work was recently published in the journal Scientific Reports.