Bubble curtain
A bubble curtain is a system that produces bubbles in a deliberate arrangement in water. It is also called pneumatic barrier. The technique is based on bubbles of air (gas) being let out under the water surface, commonly on the bottom. When the bubbles rise they act as a barrier, a curtain, breaking the propagation of waves or the spreading of particles and other contaminants.[1]
Uses
[edit]It can be used for the following purposes:
- to reduce propagation of shock waves (e.g. acoustic waves from engines or pile driving,[1][2][3] explosions etcetera),
- to reduce liquid or debris floating on the surface from spreading [4][5]
- to prevent salt intrusion[6]
- to control the movements of fish[7]
- for decoration and airing in aquariums[8]
In June 2010, Okaloosa County, Florida used air bubble curtains to help protect their Destin Pass coastline from oil produced in the Gulf of Mexico by the Deepwater Horizon oil spill. They hoped to push oil up to the surface for booms and skimming boats to collect the oil. British multinational oil company BP, who the U.S. government named as the responsible party for the oil spill, was billed for the cost of the project.[9]
Equipment
[edit]The technical system basically consists of a compressor and pipe or hose with nozzles. When used to reduce acoustic waves from pile driving, a distribution manifold made of plastic or rubber is commonly used.[10]
Offshore pile driving
[edit]Pile driving in connection to offshore construction, most importantly monopile foundations for offshore wind turbines, produces very high levels of underwater noise,[3] capable of inflicting damage to the hearing of marine organisms[11] and deter animals at tens of km from the construction site.[12][13] Large-scale bubble curtains are now routinely used to mitigate these impacts as they can attenuate the noise significantly, in particular the higher frequencies, above 1 kHz.[3]
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See also
[edit]References
[edit]- ^ a b Würsig, B.; Greene, C.R.; Jefferson, T.A. (February 2000). "Development of an air bubble curtain to reduce underwater noise of percussive piling". Marine Environmental Research. 49 (1): 79–93. doi:10.1016/S0141-1136(99)00050-1. PMID 11444016.
- ^ "Archived copy" (PDF). Archived (PDF) from the original on 2010-07-05. Retrieved 2012-05-06.
{{cite web}}: CS1 maint: archived copy as title (link) - ^ a b c Dähne, M; Tougaard, J; Carstensen, J; Rose, A; Nabe-Nielsen, J (29 September 2017). "Bubble curtains attenuate noise from offshore wind farm construction and reduce temporary habitat loss for harbour porpoises". Marine Ecology Progress Series. 580: 221–237. Bibcode:2017MEPS..580..221D. doi:10.3354/meps12257.
- ^ "Hydrotechnik Lübeck - Pneumatic Oil / Bubble Barriers". Archived from the original on 2009-03-02. Retrieved 2009-02-26.
- ^ "5.2". Archived from the original on 2005-10-26. Retrieved 2009-02-26.
- ^ Abraham, G.; Van der Burg, P.; De Vos, P. (1973). "Pneumatic barriers to reduce salt intrusion through locks". Rijkswaterstaat Communications 17. RWS-Communications. 17. The Hague, Netherlands: Rijkswaterstaat.
- ^ http://yosemite.epa.gov/R10/CLEANUP.NSF/ph/gasco+photo+gallery! OpenDocument&ExpandSection=1 Archived 2009-05-20 at the Wayback Machine
- ^ "Welcome to PET Discounters - PETdiscounters.com". www.petdiscounters.com. Archived from the original on September 10, 2012.
- ^ TEGNA. "10News WTSP - Tampa News, Florida News, Weather, Traffic - WTSP.com". 10NEWS. Archived from the original on November 24, 2016. Retrieved February 5, 2018.
- ^ "Bubble Curtain" (PDF). Archived from the original (PDF) on 2011-07-06. Retrieved 2009-02-26.
- ^ Tougaard, Jakob; Dähne, Michael (October 2017). "Why is auditory frequency weighting so important in regulation of underwater noise?". The Journal of the Acoustical Society of America. 142 (4): EL415–EL420. Bibcode:2017ASAJ..142L.415T. doi:10.1121/1.5008901. PMID 29092598. S2CID 12449068.
- ^ Brandt, Mj; Dragon, Ac; Diederichs, A; Bellmann, Ma; Wahl, V; Piper, W; Nabe-Nielsen, J; Nehls, G (28 May 2018). "Disturbance of harbour porpoises during construction of the first seven offshore wind farms in Germany". Marine Ecology Progress Series. 596: 213–232. Bibcode:2018MEPS..596..213B. doi:10.3354/meps12560.
- ^ Tougaard, Jakob; Carstensen, Jacob; Teilmann, Jonas; Skov, Henrik; Rasmussen, Per (July 2009). "Pile driving zone of responsiveness extends beyond 20 km for harbor porpoises ( Phocoena phocoena (L.))". The Journal of the Acoustical Society of America. 126 (1): 11–14. Bibcode:2009ASAJ..126...11T. doi:10.1121/1.3132523. PMID 19603857.