Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Mirror Measures Vortex Drag

09.07.2004


Airplanes generate trailing wake vortices which can be dangerous for following aircraft, especially on takeoff and landing. An onboard laser measuring device scans the air space in front of the plane, recognizes turbulence and will inform the pilot.



The volume of air traffic is constantly rising - many air routes are already overloaded. Frequent delays are encountered when machines are taking off and landing at major airports. The frequency of aircraft cannot be increased because they have to maintain a safety distance of up to six miles (11.1 kilometers). It is to ensure that the following airplane is not endangered by the vortex drag of the machine in front. This across-the-board safety distance is often more generous than required. If the position and the actual extent of the air vortex could be directly measured, the safety distance could be adjusted to the actual circumstances and shortened. Airports could then use their capacity to better effect.

“In the EU project I-Wake we are cooperating with eight teams from four different countries to develop a sensor which can determine whether the air is calm enough for a safe takeoff,” explains Thomas Peschel from the Fraunhofer Institute for Applied Optics and Precision Engineering IOF in Jena. “The optical scanner can recognize any turbulence and in future could deliver rapid and reliable measured results on board commercial aircraft. A prototype is currently being tested on a small Cessna plane.” The measurement principle is relatively simple: A laser sends pulses into the air space in front of the aircraft. The light is scattered on aerosol or dust particles and registered by a detector. As a result of the Doppler effect, the wavelength of the incoming laser pulses is shifted according to whether the airborne particles are moving towards or away from the beam. From the difference relative to the incident wavelength, a software system calculates the strength of air turbulences within fractions of a second.


Core parts of the device are two precision mirrors, measuring 11 by 15 centimeters. One of the challenges which had to be overcome was to scan the air space at a relatively high frequency of around seven times per second. To keep forces of inertia and slight subsequent deformations as low as possible, the mirrors have to be lightweight but stiff. The aluminum plate they were manufactured from was perforated to minimize its mass. The perforations run parallel to the surface on the inside in order not to deteriorate mechanical and optical properties. At the same time, the reverse side of the mirrors were retained as a closed surface in order to provide even more rigidity.

Johannes Ehrlenspiel | alfa
Further information:
http://www.fraunhofer.de

More articles from Transportation and Logistics:

nachricht Study sets new distance record for medical drone transport
13.09.2017 | Johns Hopkins Medicine

nachricht Researchers 'count cars' -- literally -- to find a better way to control heavy traffic
10.08.2017 | Florida Atlantic University

All articles from Transportation and Logistics >>>

The most recent press releases about innovation >>>

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

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Corporate coworking as a driver of innovation

22.11.2017 | Business and Finance

PPPL scientists deliver new high-resolution diagnostic to national laser facility

22.11.2017 | Physics and Astronomy

Quantum optics allows us to abandon expensive lasers in spectroscopy

22.11.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>