Researchers from Virginia Tech are exploring how creatures in nature are able to fly by flapping their wings in hopes of applying that knowledge toward designing small flying vehicles, E&T Magazine reported.
Investigators at the public university are using the flight of the fruit bats to inspire the design of "micro air vehicles" with flapping wings. They are trying to understand how the flying creatures use their wings to manipulate the air around them, according to a press release.
"Bats have different wing shapes and sizes, depending on their evolutionary function. Typically, bats are very agile and can change their flight path very quickly -- showing high maneuverability for midflight prey capture, so it's of interest to know how they do this," Danesh Tafti, the William S. Cross professor in the Department of Mechanical Engineering and director of the High Performance Computational Fluid Thermal Science and Engineering Lab at Virginia Tech, said in a statement.
Researchers said understanding how bats use their wings is extremely challenging - primarily because both experimental measurements on live creatures and the related computer analysis are complex, according to a press release.
In their study of the drug bat wings, researchers used experimental measurements of the movements of the bats' wings in real flight, and then used analysis software to see the direct relationship between wing motion and airflow around the bat wing.
Among the biggest surprises in store for the researchers was how bat wings manipulated the wing motion with correct timing to maximize the forces generated by the wing, E&T Magazine reported.
Researchers found that bat wings became distorted during flapping.
"For example, it increases the area of the wing by about 30 percent to maximize favorable forces during the downward movement of the wing, and it decreases the area by a similar amount on the way up to minimize unfavorable forces," researchers said in a press release.
The force coefficients generated by the wing are "about two to three times greater than a static airfoil wing used for large airplanes," Kamal Viswanath, a co-author who was a graduate research assistant working with Tafti when the work was performed and is now a research engineer at the U.S. Naval Research Lab's Laboratories for Computational Physics and Fluid Dynamics, said in a statement.
This study was just an initial step in the researchers' work.
Viswanath said researchers hope to explore the seemingly complex motion of the bat wing into simpler motions, which is necessary to make a bat-inspired flying robot,"
For the flying device, they want to keep the wing motion as simple as possible, but with the same force production as that of a real bat.
"We'd also like to explore other bat wing motions, such as a bat in level flight or a bat trying to maneuver quickly to answer questions, including: What are the differences in wing motion and how do they translate to air movement and forces that the bat generates? And finally, how can we use this knowledge to control the flight of an autonomous flying vehicle?" Tafti added.
Researchers reported their findings in the journal Physics of Fluids.
