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 use oil instead of water. The advantage is that the increased viscosity will allow the flow to be a higher speed (and thus easier to maintain in a stable manner) for a lower Reynolds number.
Often, a tunnel will be co-located with other experimental facilities such as a wave flume at a Ship model basin.
Cavitation studies
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.
List of water tunnels (cavitation tunnels)
Australia
- "Australian Maritime College". AMC
Brazil
- Laboratory of Naval and Oceanic Engineering (NAVAL), Institute for Technological Research (IPT) of São Paulo.
Canada
France
- "Tunnel de Cavitation" Ecole Navale, Lanveoc
- "Grand Tunnel Hydrodynamique" Bassin d'Essais des Carènes, Val de Reuil
- "TH8.2V : Tunnels Hydrodynamiques 8 ou 2 m3/s"
Germany
- Multiple cavitation tunnels at the Versuchsanstalt für Wasserbau und Schiffbau, Berlin
- Cavitation tunnel at the University Duisburg-Essen, Institute of Ship Technology, Ocean Engineering and Transport Systems, University Duisburg-Essen
- Cavitation tunnel at Potsdam Ship Model Basin, Potsdam
- Large Cavitation tunnel at Hamburg Ship Model Basin, Hamburg
- Multiple cavitation tunnels at the Oskar von Miller Institut, Technical University of Munich
India
- Fluid Control Research Institute, Palakkad, Kerala.
- Cavitation Tunnel of the Naval Science and Technology Labs at Visakhapatnam.
- Department of Aerospace Engineering, Indian Institute of Technology, Kharagpur
- Indian Institute of Technology Madras.
Iran
- Applied Hydrodynamics Laboratory, Iran University of Science and Technology, Narmak, Tehran.
- Marine Engineering Laboratory, Sharif University of Technology, 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
Norway
Spain
- CEHIPAR (Canal de Experiencias Hidrodinámicas de El Pardo), El Pardo (Madrid), Spain.
Serbia
Switzerland
- High Speed Cavitation Tunnel at LMH: Lab. of Hydraulic Machines, EPFL: Ecole Polytechnique Federale de Lausanne, Switzerland
Taiwan
Turkey
United Kingdom
United States
See also
References
External links