Forum für Wissenschaft, Industrie und Wirtschaft

Hauptsponsoren:     3M 
Datenbankrecherche:

 

Engineer Looks to Dragonflies, Bats for Flight Lessons

17.12.2012
Ever since the Wright brothers, engineers have been working to develop bigger and better flying machines that maximize lift while minimizing drag.

There has always been a need to efficiently carry more people and more cargo. And so the science and engineering of getting large aircraft off the ground is very well understood.

But what about flight at a small scale? Say the scale of a dragonfly, a bird or a bat?

Hui Hu, an Iowa State University associate professor of aerospace engineering, said there hasn’t been a need to understand the airflow, the eddies and the spinning vortices created by flapping wings and so there haven’t been many engineering studies of small-scale flight. But that’s changing.

The U.S. Air Force, for example, is interested in insect-sized nano-air vehicles or bird-sized micro-air vehicles. The vehicles could fly microphones, cameras, sensors, transmitters and even tiny weapons right through a terrorist’s doorway.

So how do you design a little flier that’s fast and agile as a house fly?

Hu says a good place to start is nature itself.

And so for a few years he’s been using wind tunnel tests and imaging technologies to learn why dragonflies and bats are such effective fliers. How, for example, do flapping frequency, flight speed and wing angle affect the lift and thrust of a flapping wing?

Hu’s studies of bio-inspired aerodynamic designs began in 2008 when he spent the summer on a faculty fellowship at the Air Force Research Laboratory at Eglin Air Force Base in Florida. Over the years he’s published papers describing aerodynamic performance of different kinds of flapping wings.

A study based on the dragonfly, for example, found the uneven, sawtooth surface of the insect’s wing performed better than a smooth airfoil in the slow-speed, high-drag conditions of small-scale flight. Using particle image velocimetry – an imaging technique that uses lasers and cameras to measure and record flows – Hu found the corrugated wing created tiny air cushions that kept oncoming airflow attached to the wing’s surface. That stable airflow helped boost performance in the challenging flight conditions. By describing the underlying physics of dragonfly flight, Hu and Jeffery Murphy, a former Iowa State graduate student, won a 2009 Best Paper Award in applied aerodynamics from the American Institute of Aeronautics and Astronautics.

Another study of bat-like wings found the built-in flexibility of membrane-covered wings helped decrease drag and improve flight performance.

And what about building tiny flying machines that use flapping wings? Can engineers come up with a reliable way to make that work?

Hu has been looking into that, too.

He’s using piezoelectrics, materials that bend when subject to an electric current, to create flapping movements. That way flapping depends on feeding current to a material, rather than relying on a motor, gears and other moving parts.

Hu has also used his wind tunnel and imaging tests to study how pairs of flapping wings work together – just like they do on a dragonfly. He learned wings flapping out of sync (one wing up while the second is down) created more thrust. And tandem wings working side by side, rather than top to bottom, maximize thrust and lift.

Hu said these kinds of physics and aerodynamics lessons – and many more – need to be learned before engineers can design effective nano- and micro-scale vehicles.

And so he’s getting students immersed in the studies.

Hu has won a $150,000, three-year National Science Foundation grant that sends up to 12 Iowa State students to China’s Shanghai Jiao Tong University for eight weeks of intensive summer research. The students work at the university’s J.C. Wu Aerodynamics Research Center to study bio-inspired aerodynamics and engineering problems.

“We’re just now learning what makes a dragonfly work,” Hu said. “There was no need to understand flight at these small scales. But now the Defense Advanced Research Projects Agency and the Air Force say there is a need and so there’s an effort to work on it. We’re figuring out many, many interesting things we didn’t know before.”

Hui Hu, Aerospace Engineering, 515-294-0094, huhui@iastate.edu
Mike Krapfl, News Service, 515-294-4917, mkrapfl@iastate.edu

Mike Krapfl | Newswise
Further information:
http://www.iastate.edu

More articles from Machine Engineering:

nachricht Management platform enables secure and simple remote access
29.06.2015 | Siemens AG

nachricht ShortPulse: Shorter pulses for more efficiency and precision
18.06.2015 | neoLASE GmbH

All articles from Machine Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: Forschungsschiff Heincke seit 25 Jahren im Dienst der Wissenschaft

Ein Vierteljahrhundert alt, über 900.000 Kilometer (488.842 nautische Meilen) gefahren und trotzdem auf dem neuesten wissenschaftlichen und technischen Stand: Die Indienststellung des Forschungsschiffes Heincke jährt sich am 8. Juli 2015 zum 25. Mal.

Wissenschaftler des Alfred-Wegener-Instituts, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), das die Heincke betreibt, nehmen ebenso regelmäßig an...

Im Focus: Solardächer produzieren Strom für Fahrzeuge

Studentische Industriekooperation zwischen HAW Hamburg und Webasto erarbeitet Ergebnisse für EU-Zertifizierungsprozess von Solardächern zur Verbesserung der Öko-Bilanz von Fahrzeugen.

Unter der Leitung von Dr.-Ing. Volker Skwarek, Professor für technische Informatik an der HAW Hamburg, erarbeiteten sechs Studierende des...

Im Focus: Viaducts with wind turbines, the new renewable energy source

Wind turbines could be installed under some of the biggest bridges on the road network to produce electricity. So it is confirmed by calculations carried out by a European researchers team, that have taken a viaduct in the Canary Islands as a reference. This concept could be applied in heavily built-up territories or natural areas with new constructions limitations.

The Juncal Viaduct, in Gran Canaria, has served as a reference for Spanish and British researchers to verify that the wind blowing between the pillars on this...

Im Focus: Aus alt mach neu - Rohstoffquelle Elektroschrott

Der Markt für Unterhaltungselektronik boomt: Rund 60 Millionen Fernsehgeräte wurden im letzten Jahr in Europa verkauft. Früher oder später werden sie zurückkehren – als Elektroschrott.

Die Recycling-Industrie hat darauf reagiert: Kupfer, Aluminium, Eisen- und Edelmetalle sowie ausgewählte Kunststoffe werden bereits wiederverwertet. Allerdings...

Im Focus: Radar schützt vor Weltraummüll

Die Bedrohung im All durch Weltraummüll ist groß. Aktive Satelliten und Raumfahrzeuge können beschädigt oder zerstört werden. Ein neues, nationales Weltraumüberwachungssystem soll ab 2018 vor Gefahren im Orbit schützen. Fraunhofer-Forscher entwickeln das Radar im Auftrag des DLR Raumfahrtmanagement.

Die »Verkehrssituation« im All ist angespannt: Neben unzähligen Satelliten umkreisen Weltraumtrümmer wie beispielsweise ausgebrannte Raketenstufen und...

Alle Focus-News des Innovations-reports >>>

Anzeige

Anzeige

IHR
JOB & KARRIERE
SERVICE
im innovations-report
in Kooperation mit academics
Veranstaltungen

Flurförderzeuge im Zeichen der Zeit

03.07.2015 | Veranstaltungen

Aktuelles aus Forschung und Betrieb: 27. Deutscher Flammentag

02.07.2015 | Veranstaltungen

Call for ideas: Gute Ideen für bessere Städte

02.07.2015 | Veranstaltungen

 
B2B-VideoLinks
Weitere VideoLinks >>>
Aktuelle Beiträge

Siemens erhält Auftrag für Offshore-Windkraftwerk in Großbritannien

03.07.2015 | Unternehmensmeldung

Flurförderzeuge im Zeichen der Zeit

03.07.2015 | Veranstaltungsnachrichten

Kompakter Time Converter für zuverlässigen Einsatz in rauen Umgebungen

03.07.2015 | Energie und Elektrotechnik