Scouring induced by a confined propeller jet nearby a vertical quay structure : scale model tests

The turbulent jet generated by a ship propeller may cause damages to sediment beds due to its erosive potential. When local erosion or scour appears nearby harbour infrastructure like berthing quay walls, the risk of failure increases. To further develop approaches for the determination of the scour depth and geometry at quay walls as a function of time, scale-model experiments were carried out in a flume using different boundary conditions. The temporal development of the scour geometry was obtained by scanning the bed at predefined time-steps using an array of 16 ultrasonic sensors. These measurements were supplemented by additional measurements using a Vectrino Profiler and the Structurefrom-Motion-Photogrammetry technique. The results from the tests show consistent relations between the measured maximum scour depth and the wall and bed clearance distances, respectively, as well as the rotational speed of the propeller. Contrary to the expectations according to published equations to estimate scour depths, the results obtained in this study show a direct linear dependency between the maximum scour depth and the wall clearance distances for all the tested boundary conditions. Moreover, the data also reveal a consistent functional relationship between the main scour hole dimensions and the eroded volume.

Schlagworte

Confined propeller wash

closed-type quay wall

sediment transport

propeller jet induced scour

scale model tests

DDC Class

620: Engineering

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publishedVersion

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http://rightsstatements.org/vocab/InC/1.0/

Name

MaciasLezcano-ScouringInducedByAConfinedPropellerJetNearbyAVerticalQuayStructu-1198-1-final.pdf

Type

main article

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1.26 MB

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Scouring induced by a confined propeller jet nearby a vertical quay structure : scale model tests