Three-Dimensional Scour at Submarine Pipelines
Publication: Journal of Hydraulic Engineering
Volume 138, Issue 9
Abstract
This paper presents results of an experimental study on three-dimensional scour at submarine pipelines with uniform sediment under a unidirectional current in clear-water conditions. The data show that propagation of the scour hole in the transverse direction of flow may be divided into a rapid and a slack phase of development. The former is characterized by a higher and constant velocity, whereas the latter a lower and reducing propagation velocity. Four nondimensional parameters are identified and their effects examined experimentally. Pipeline embedment and water depth to pipeline diameter ratios, which represent the stability force, inhibit the scouring process, resulting in a reduced propagation velocity and a dominant slack phase of development. Conversely, Froude number and Shields parameters represent the environment force; they enhance the scouring process, causing a high propagation velocity and a dominant rapid phase of development. The experimental results reveal that the scour process is not sensitive to Shields parameter under clear-water conditions but is closely related to the other three parameters. The effect of all the parameters can be viewed in a balance between the environment and stability forces.
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Acknowledgement
The authors acknowledge the support from DHI-NTU Water & Environment Research Center and Education Hub. The first author also wishes to acknowledge the financial support given by Nanyang Technological University for his doctoral study.
References
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© 2012 American Society of Civil Engineers.
History
Received: Jul 20, 2011
Accepted: Feb 23, 2012
Published online: Feb 25, 2012
Published in print: Sep 1, 2012
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