Uncommon Descent Serving The Intelligent Design Community

Insects defy aerodynamic laws


From ScienceDaily:

The maneuvers of flying insects are unmatched by even the best pilots, and this might be due to the fact that these critters don’t obey the same aerodynamic laws as airplanes, a team of New York University researchers has found.

“We’ve known for quite a while that the aerodynamic theory for airplanes doesn’t work so well in predicting the force of lift for flapping wings,” says Leif Ristroph, an assistant professor at NYU’s Courant Institute of Mathematical Sciences who directed the study. “We found that the drag or wind resistance also behaves very differently, and we put together a new law that could help explain how insects move through the air.”

“To double its flight speed, an airplane must increase its thrust four-fold to counter the stronger wind resistance,” Ristroph explains in outlining the law. “In contrast, we found that flapping wings have a drag that is in direct proportion to its flight speed — to go twice as fast, an insect simply needs to double its thrust.” More. Paper. (paywall) – Natalie Agre, Stephen Childress, Jun Zhang, and Leif Ristroph. Linear drag law for high-Reynolds-number flow past an oscillating body. Physical Review Fluids, July 2016 DOI: 10.1103/PhysRevFluids.1.033202

We must fire these dreadful insects and get ourselves other, more correct ones.

See also: Life continues to ignore what evolution experts say

Follow UD News at Twitter!

... So we should go with planes with flapping wings? (I don't think so :-) ). Helicopters come closest. They fly by beating the air into submission. leodp
OT: Spider silk amazes researchers again!
Spiders spin unique phononic material - July 25, 2016 Excerpt: Scientists at Rice University and in Europe and Singapore studied the microstructure of spider silk to see how it transmits phonons, quanta of sound that also have thermal properties. They suggested what they learned could be useful to create strong synthetic fibers with silk-like properties.,,, New discoveries about spider silk could inspire novel materials to manipulate sound and heat in the same way semiconducting circuits manipulate electrons, according to scientists at Rice University, in Europe and in Singapore. A paper in Nature Materials today looks at the microscopic structure of spider silk and reveals unique characteristics in the way it transmits phonons, quasiparticles of sound. The research shows for the first time that spider silk has a phonon band gap. That means it can block phonon waves in certain frequencies in the same way an electronic band gap - the basic property of semiconducting materials - allows some electrons to pass and stops others. The researchers wrote that their observation is the first discovery of a "hypersonic phononic band gap in a biological material." How the spider uses this property remains to be understood, but there are clear implications for materials, according to materials scientist and Rice Engineering Dean Edwin Thomas, who co-authored the paper. He suggested that the crystalline microstructure of spider silk might be replicated in other polymers. That could enable tunable, dynamic metamaterials like phonon waveguides and novel sound or thermal insulation, since heat propagates through solids via phonons.,,, "(Spider) silk has a lot of different, interesting microstructures, and our group found we could control the position of the band gap by changing the strain in the silk fiber," Thomas said. "There's a range of frequencies that are not allowed to propagate. If you broadcast sound at a particular frequency, it won't go into the material.",,, Though silk has been studied for thousands of years, it has only recently been analyzed for its acoustic properties.,,, "Right now, we don't know how to do any of this in other macromolecular fiber materials," Thomas said. "There's been a fair amount of investigation on synthetic polymers like nylon, but nobody's ever found a band gap." http://phys.org/news/2016-07-spiders-unique-phononic-material.html
Praise Darwin! Andre

Leave a Reply