Chronology Current Month Current Thread Current Date [Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

[Phys-L] Bank Effect and the Ever Given Mishap

I may have mentioned reports of the curious trajectory of this container ship on this list, as 'bouncing from the West bank to the East bank where it lodged'
There are pilots on this list, but this bouncing action would not have registered as central to them. The nearest equivalent behavior of aircraft is "the bunny hop" whereby a student pilot approaches a runway at too high a speed or too great a rate of descent and hops back into the air once or several times. (I may hold the record of seven hops in a tiny Tipsy Nipper.)  This vessel did not bounce off the West Bank, but instead experienced the Bank effect, which has much the same effect hydrodynamically, without any sidewall contact - as a bunny-hop; which is a greatly accentuated  Ground Effect  like the increase in lift when an aircraft is within a half span of the ground.
[from Summary of PhD Thesis: 2014]"Overall the magnitude of the bank effects: the longitudinal forceand both lateral forces (at the fore and aft perpendicular) increasewith: A higher forward speed of the ship A more loaded propeller (higher propeller rate) A lower under keel clearance A more confined sailing area; steeper banks, smallerdistance between port and starboard bank
"The closer the distance between ship and bankThe longitudinal force of the bank effects always acts on the shipas an augmented resistance. The lateral force at the aftperpendicular acts always as an attraction force directed towardsthe nearest bank. In deep water the lateral force at the forwardperpendicular is also an attraction force towards the nearest bankwhile in very shallow water this force is always a repulsion forcedirected away from the nearest bank. In between there is atransition from repulsion to attraction which shifts with theforward speed of the ship and relative water depth.
[Experiment Based Mathematical Modelling of Ship-Bank InteractionEvert Lataire: PhD thesis UGhent 2014]from https://biblio.ugent.be/publication/5778797/file/5831702.pdfExperiment based mathematical modelling of ship-bank interaction

|
|
| |
Experiment based mathematical modelling of ship-bank interaction

Lataire, Evert

|

|

|

Here is the transponder track of the action in that section of the Suez.Container ship Ever Given blocked Suez Canal

|
|
|
| | |

|

|
|
| |
Container ship Ever Given blocked Suez Canal

|

|

|