bank effect
{{short description|Tendency of the stern of a ship making way to swing toward the near bank}}
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Image:Ship's limited channel effects (Blockage Effects) NT.PNG
The bank effect (channel effect, bank suction, bank cushion, stern suction, ship-bank interaction) is the tendency of the stern of a ship to swing toward the near bank when operating in a river or constricted waterway.{{Cite news|title=The bank effect and the big boat blocking the Suez |url=https://www.ft.com/content/171c92ec-0a44-4dc5-acab-81ee2620d3c1|access-date=2021-03-27|website= Financial Times|date=25 March 2021 |last1=Greeley |first1=Brendan }} Paywall
Phenomenon
The asymmetric flow around a ship induced by the vicinity of banks causes pressure differences (Bernoulli's principle) between port and starboard sides. As a result, a lateral force will act on the ship, mostly directed towards the closest bank, as well as a yawing moment pushing her bow towards the centre of the waterway. The squat effect increases due to the decreased blockage.
This phenomenon depends on many parameters, such as bank shape, water depth, ship-bank distance, ship properties, ship speed and propeller action. A reliable estimation of bank effects is important for determining the limiting conditions in which a ship can safely navigate a waterway.
Examples
It was cited as a possible cause of the 2021 Suez Canal obstruction by the cargo ship Ever Given.
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See also
- {{annotated link|Coandă effect}}
- {{annotated link|Bernoulli's principle}}
- {{annotated link|Continuity equation}}
- {{annotated link|Squat effect}}
References
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External links
- [http://www.bankeffects.ugent.be/meas.html Model tests demonstrating the bank effect] for International Conference on Ship Manoeuvring in Shallow and Confined Water (MASHCON) at Ghent University January 2010
- [https://shallowwater.ugent.be/EN/kc_ond_oev_EN.htm Bank Effects] at Knowledge Centre, Manoeuvring in Shallow and Confined Water Ghent University
- [https://shallowwater.ugent.be/EN/kc_conf_banks_EN.htm MASHCON 1] : Bank Effects
- [https://shallowwater.ugent.be/EN/kc_conf_sts_EN.htm MASHCON 2] : Ship to Ship Interaction
- [https://lockeffects.ugent.be/EN/kc_conf_locks_call_EN.htm MASHCON 3] : Lock effects
- [https://shallowwater.ugent.be/EN/kc_conf_bottom_EN.htm MASHCON 4] : Ship Bottom Interaction
- [https://mashcon2019.ugent.be/EN/mashcon2019_call_EN.htm MASHCON 5] : waves, wind and current
- [https://shallowwater.ugent.be/EN/kc_conf_mashcon6.htm MASHCON 6] : Port Manoeuvres (May 2022)
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