Are Flexible, Flapping Flying Machines in our Future?

Modern aircraft have been fabulously successful with rigid wings and rotors. But just imagine the flying machines that would be possible if we could understand and harness the most efficient and acrobatic airfoils in nature: the flexible wings of the bat.

The aerodynamics of "compliant" structures, such as bat wings, are very complicated because both the structure and airflow change and adapt to each other in a highly nonlinear way. Bats' wing bones are even flexible, unlike those of birds, which gives the mammals added control but is an additional challenge for scientists trying to understand them.

Kenny Breuer's research group at Brown University is designing a series of fundamental experiments that will allow scientists to isolate, observe and analyze a variety of specific flow-structure interactions that are important in understanding bat flight and, in general, the aerodynamics of compliant structures. Ultimately, Breuer expects that experiments like these will yield insights enabling new generations of flying machines that are impossible to consider today.

In his talk at the 61st Annual Meeting of the APS Division of Fluid Dynamics in San Antonio, Arnold Song, who is one member of this research group, will describe the basic motions -- and their aerodynamic implications -- that he and his colleagues at Brown have discovered so far by measuring how paddles and stretched ribbons of sailcloth vibrate in manmade breezes in a wind tunnel.

As the airflow increases, for example, a paddle on a post first twists and then flaps, like a stop sign being pummeled by hurricane-force winds. The ribbon's behavior is more complicated, but also essential for understanding how bat wings or other compliant structures generate lift so efficiently.

Song's talk, "On Vortex Induced Motion in Compliant Structures," will be held on Sunday, November 23, 2008 at the 61st Annual Meeting of the American Physical Society.

Source: American Institute of Physics

Related stories:

Molecular evolution is echoed in bat ears
Echolocation may have evolved more than once in bats, according to new research from the University of Bristol published this week in Proceedings of the National Academy of Sciences (PNAS).
Why wind turbines can mean death for bats
Power-generating wind turbines have long been recognized as a potentially life-threatening hazard for birds. But at most wind facilities, bats actually die in much greater numbers. Now, researchers reporting in Current Biology, a Cell Press journal, on August 26th think they know why.
Researchers studying how singing bats communicate
Bats are the most vocal mammals other than humans, and understanding how they communicate during their nocturnal outings could lead to better treatments for human speech disorders, say researchers at Texas A&M University.
Whales evolved biosonar to chase squid into the deep
Behind the sailor's lore of fearsome battles between sperm whale and giant squid lies a deep question of evolution: How did these leviathans develop the underwater sonar needed to chase and catch squid in the inky depths"
Moths mimic sounds to survive
In a night sky filled with hungry bats, good-tasting moths increase their chances of survival by mimicking the sounds of their bad-tasting cousins, according to a new Wake Forest University study.
Figuring out function from bacteria's bewildering forms
The constellation of shapes and sizes among bacteria is as remarkable as it is mysterious. Why should Spirochaeta halophila resemble a bedspring coil, Stella a star and Clostridium cocleatum a partly eaten donut? No one really knows.
Engineers, Biologists Join to Explore Bat-Biting Mechanics
The ability to bite off more than one can chew is related to the anatomy of the skull, contend University of Massachusetts Amherst scientists, who are putting their heads together to explore the relationship between the biomechanics of biting and the evolution of skull shape diversity in bats.
Liquidmetal: Redefining metals for the 21st century
A revolution in metals has arrived. NASA, the California Institute of Technology (Caltech) and the U.S. Department of Energy united to help develop a new building material. "Liquidmetal" is a type of alloy, a mix of three or more metals, with characteristics similar to plastic that cools quickly and has more than twice the strength of titanium.

News discussion:

Physics news