Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Effortless sailing with fluid flow cloak

12.08.2011
Duke engineers have already shown that they can "cloak" light and sound, making objects invisible -- now, they have demonstrated the theoretical ability to significantly increase the efficiency of ships by tricking the surrounding water into staying still.

"Ships expend a great deal of energy pushing the water around them out of the way as they move forward," said Yaroslav Urzhumov, assistant research professor in electrical and computer engineering at Duke's Pratt School of Engineering. "What our cloak accomplishes is that it reduces the mass of fluid that has to be displaced to a bare minimum.

"We accomplish this by tricking the water into being perfectly still everywhere outside the cloak," Urzhumov said. "Since the water is still, there is no shear force, and you don't have to drag anything extra with your object. So, comparing a regular vessel and a cloak of the same size, the latter needs to push a much smaller volume of water, and that's where the hypothesized energy efficiency comes from."

The results of Urzhumov's analysis were published online in the journal Physical Review Letters. The research was supported by the U.S. Office of Naval Research and a Multidisciplinary University Research Initiative (MURI) grant through the U.S. Army Research Office. Urzhumov works in the laboratory of David R. Smith, William Bevan Professor of electrical and computer engineering at Duke.

While the cloak postulated by Urzhumov differs from other cloaks designed to make objects seem invisible to light and sound, it follows the same basic principles – the use of a man-made material that can alter the normal forces of nature in new ways.

In Urzhumov's fluid flow cloak, he envisions the hull of a vessel covered with porous materials – analogous to a rigid sponge-like material – which would be riddled with holes and passages. Strategically placed within this material would be tiny pumps, which would have the ability to push the flowing water along at various forces.

"The goal is make it so the water passing through the porous material leaves the cloak at the same speed as the water surrounding by the vessel," Urzhumov said. "In this way, the water outside the hull would appear to be still relative to the vessel, thereby greatly reducing the amount of energy needed by the vessel to push vast quantities of water out of the way as it progresses."

While the Duke invisibility cloak involved a man-made structure – or metamaterial – based on parallel rows of fiberglass slats etched with copper, Urzhumov envisions a different sort of metamaterial for his fluid flow cloak.

"In our case, I see this porous medium as a three-dimensional lattice, or array, of metallic plates," he said. "You can imagine a cubic lattice of wire-supported blades, which would have to be oriented properly to create drag and lift forces that depend on the flow direction. In addition, some of the cells of this array would be equipped with fluid-accelerating micro-pumps."

Urzhumov explained that when a regular vessel moves through fluid, it also pushes and displaces a volume of water that greatly exceeds the volume of the vessel itself. That is because in a viscous fluid like water, an object cannot just move a single layer of water without all others; the shear force effectively attaches an additional mass of water to the object.

"When you try to drag an object on a fishing line through water, it feels much heavier than the object itself, right?" he said. "That's because you are dragging an additional volume of water with it."

Based on this understanding of the flow cloaking phenomenon, Urzhumov believes that the energy expended by the micropumps could be significantly less than that needed to push an uncloaked vessel through the water, leading to the greatly improved efficiency.

Richard Merritt | EurekAlert!
Further information:
http://www.duke.edu

More articles from Physics and Astronomy:

nachricht Study offers new theoretical approach to describing non-equilibrium phase transitions
27.04.2017 | DOE/Argonne National Laboratory

nachricht SwRI-led team discovers lull in Mars' giant impact history
26.04.2017 | Southwest Research Institute

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

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

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>