Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

NYU’S Childress demonstrates tool for studying hovering flight at international science meeting

21.02.2006


A tool for examining hovering flight of insects and birds could allow researchers to study other matters pertaining to locomotion, Stephen Childress, a professor at New York University’s Courant Institute of Mathematical Sciences, demonstrated at the American Association for the Advancement of Science (AAAS) annual meeting in St. Louis. The findings were part of a symposium, "How Insects Fly," which also included researchers from Cornell University and the California Institute of Technology.



Previous research in this area was conducted through observations of a small pteropod mollusk, or "sea butterfly," whose locomotion in water is similar to that of a butterfly’s flight. That revealed two modes of locomotion: in one, cilia mode, the organism swims forward much like a micro-organism, using waves of beating cilia, or hair-like structures; in another, flapping mode, the wings are extended and flapped back and forth in a symmetrical manner, propelling the body forward. These results showed that this particular organism was able to use both modes: one pertaining to the microorganisms, the other to the insects or birds. As the pteropods grew, observations by Childress with his colleague, Robert Dudley, a biologist at the University of California, Berkeley, showed that the wings enabled more rapid swimming. Extrapolating the data backwards to small size, it was found that wings ceased to be effective at a critical size, establishing a transition size for winged flight.

Building on this scholarship, Childress and his colleagues at the Courant Institute’s Applied Mathematics Laboratory sought ways to study free flight in the laboratory. They first replicated the forward flight of the pteropod by driving a horizontal rigid blade in a vertical oscillation while immersed in fluid. The blade was mounted on a vertical shaft, free to rotate in either direction. The blade flapped horizontally according to Newton’s law of motion. It was found that the transition seen in the pteropods occurred also with the flapping blade. The transition depends upon both the size of the blade and the frequency of flapping. The researchers were thus able to study the transition by varying the frequency instead of the size. Below a certain frequency the blade ceased to rotate.


To simulate the hovering flight of a flapping body, the researchers created a vertical "oscillating wind tunnel," by using a large speaker operated in the range 10-100 Hertz and driving an oscillating column of air in a vertical, cylindrical flight chamber. They then simulated a bug using a small winged body made of paper and placing it in the airflow. The wings are driven to flap and the bug hovers in the flow. This allows analysts to compare the hovering of a passive flexible body in an oscillating airflow with that of an active flapper. The researchers then measured the minimum airflow amplitude needed for geometrically similar bugs of various sizes to hover in the oscillating air and were able to show how the optimal flapping frequency changes with size.

Childress and his colleagues are presently comparing these observations of free passive flapping flight with models of insect flight. The work promises to provide a new approach to the study of flapping flight, enabling studies of free hovering of winged bodies.

James Devitt | EurekAlert!
Further information:
http://www.nyu.edu

More articles from Life Sciences:

nachricht BigH1 -- The key histone for male fertility
14.12.2017 | Institute for Research in Biomedicine (IRB Barcelona)

nachricht Guardians of the Gate
14.12.2017 | Max-Planck-Institut für Biochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Plasmonic biosensors enable development of new easy-to-use health tests

14.12.2017 | Health and Medicine

New type of smart windows use liquid to switch from clear to reflective

14.12.2017 | Physics and Astronomy

BigH1 -- The key histone for male fertility

14.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>