Water tunnel (hydrodynamic)

A water tunnel is an experimental facility used for testing the hydrodynamic behavior of submerged bodies in flowing water. It functions similar to a recirculating wind tunnel, but uses water as the working fluid, and related phenomena are investigated, such as measuring the forces on scale models of submarines or lift and drag on hydrofoils. Water tunnels are sometimes used in place of wind tunnels to perform measurements because techniques like particle image velocimetry (PIV) are easier to implement in water. For many cases as long as the Reynolds number is equivalent, the results are valid, whether a submerged water vehicle model is tested in air or an aerial vehicle is tested in water. For low Reynolds number flows, tunnels can be made to run oil instead of water. The advantage is that the increased viscosity will allow the flow to be a faster speed (and thus easier to maintain in a stable manner) for a lower Reynolds number.

Cavitation tunnel of the Versuchsanstalt für Wasserbau und Schiffbau in Berlin

Whereas in wind tunnels the driving force is usually sophisticated multiblade propellers with adjustable blade pitch, in water and oil tunnels the fluid is circulated with pumps, effectively using a net pressure head difference to move the fluid rather than imparting momentum on it directly. Thus the return section of water and oil tunnels does not need any flow management; typically it is just a pipe sized for the pump and desired flow speeds. The upstream section of a water tunnels generally consists of a pipe (outlet from the pump) with several holes along its side and with the end open followed by a series of coarse and fine screens to even the flow before the contraction into the test section. Wind tunnels may also have screens before the contraction, but in water tunnels they may be as fine as the screen used in window openings and screen doors.

Additionally, many water tunnels are sealed and can reduce or increase the internal static pressure, to perform cavitation studies. These are referred to as cavitation tunnels.

Cavitating propeller model in 'David Taylor Model Basin'

Methods

Because it is a high-speed phenomenon, a special procedure is needed to visualize cavitation. The propeller, attached to a dynamometer, is placed in the inflow, and its thrust and torque is measured at different ratios of propeller speed (number of revolutions) to inflow velocity. A stroboscope synchronized with the propeller speed "freezes" the cavitation bubble. By this means, it is possible to determine if the propeller would be damaged by cavitation. To ensure similarity to the full-scale propeller, the pressure is lowered, and the gas content of the water is controlled.

Often, a tunnel will be co-located with other experimental facilities such as a wave flume at a Ship model basin.

List of water tunnels (cavitation tunnels)

Australia
  • "Australian Maritime College". AMC[1]

Brazil
  • Laboratory of Naval and Oceanic Engineering (NAVAL), Institute for Technological Research (IPT) of São Paulo.

Canada

France

Germany
  • Multiple cavitation tunnels at the Versuchsanstalt für Wasserbau und Schiffbau,[6] Berlin
  • Cavitation tunnel at the University Duisburg-Essen, Institute of Ship Technology, Ocean Engineering and Transport Systems, [7] University Duisburg-Essen
  • Cavitation tunnel at Potsdam Ship Model Basin,[8] Potsdam
  • Large Cavitation tunnel at Hamburg Ship Model Basin,[9] Hamburg
  • Multiple cavitation tunnels at the Oskar von Miller Institut,[10] Technical University of Munich

India

Iran
  • Applied Hydrodynamics Laboratory, Iran University of Science and Technology,[11] Narmak, Tehran.
  • Marine Engineering Laboratory, Sharif University of Technology,[12][13] Azadi Av., Tehran.

Italy
  • Department of Naval Architecture, University of Genoa.
  • INSEAN Cavitation facility, INSEAN (National Institute of Studies and Experiments in Naval Architecture), Rome.

The Netherlands
  • Large Cavitation Tunnel and High Speed Cavitation Tunnel at Maritime Research Institute Netherlands in Wageningen
  • Twente Water Tunnel facility at University of Twente[14]

Norway

Spain
  • CEHIPAR (Canal de Experiencias Hidrodinámicas de El Pardo), , El Pardo (Madrid), Spain.

Serbia

Switzerland

Taiwan

United Kingdom

United States
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See also

References
  1. "Home". Australian Maritime College - University of Tasmania, Australia. Retrieved 2018-09-30.
  2. Canada, Government of Canada. National Research Council. "Cavitation Tunnel - National Research Council Canada". www.nrc-cnrc.gc.ca. Retrieved 2018-09-30.
  3. "Accueil | Ecole Navale". www.ecole-navale.fr (in French). Retrieved 2018-09-30.
  4. cadre Archived 2006-02-10 at the Wayback Machine
  5. "Tunnels Hydrodynamiques 8 ou 2 m³/s". www.cerg-lab.com. Retrieved 2016-04-08.
  6. "Test Facilities". Archived from the original on May 3, 2008.
  7. "Cavitation Tunnel". www.uni-due.de. Retrieved 2018-09-30.
  8. "SVA | Schiffbau-Versuchsanstalt Potsdam". www.sva-potsdam.de (in German). Retrieved 2018-09-30.
  9. "Conventional Cavitation Tunnels". www.hsva.de (in German). Retrieved 2018-09-30.
  10. "TUM Lehrstuhl und Versuchsanstalt für Wasserbau und Wasserwirtschaft - Infrastruktur der Versuchsanstalt Obernach" (in German). Archived from the original on Feb 26, 2012.
  11. Archived April 9, 2010, at the Wayback Machine
  12. Archived November 13, 2007, at the Wayback Machine
  13. Archived August 23, 2007, at the Wayback Machine
  14. "Physics of Fluids - Research - Facilities - Twente Water Tunnel". pof.tnw.utwente.nl. Retrieved 2018-09-30.
  15. "NTOU-Systems Engineering and Naval Architecture - Research Center". www.se.ntou.edu.tw. Retrieved 2018-09-30.
  16. "University unveils naval test facility - Taipei Times". www.taipeitimes.com. Retrieved 2018-09-30.
  17. "University unveils naval test facility - Taipei Times". www.taipeitimes.com. Retrieved 2018-09-30.
  18. "Emerson Cavitation Tunnel - Engineering, School of - Newcastle University". www.ncl.ac.uk. Retrieved 2018-09-30.
  19. GTWT Archived 2006-05-21 at the Wayback Machine
  20. Large Cavitation Channel (LCC) Archived 2007-08-07 at the Wayback Machine
  21. "Water Tunnel". The William States Lee College of Engineering. June 1, 2009. Archived from the original on July 28, 2017.
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