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Current-induced scour beneath initially elevated subsea pipelines

Citation

Lee, JY and Hardjanto, FA and Cossu, R and Chai, S and Leong, ZQ and Forrest, AL, Current-induced scour beneath initially elevated subsea pipelines, Applied Ocean Research, 82 pp. 309-324. ISSN 0141-1187 (2019) [Refereed Article]

Copyright Statement

Copyright 2018 Elsevier Ltd.

DOI: doi:10.1016/j.apor.2018.11.011

Abstract

When a subsea pipeline is laid on an uneven seabed, certain sections may have an initial elevation with respect to the far-field seabed, eo, and thus potentially affecting the on-bottom stability of the pipeline. This paper focuses on quantifying the effects of the upstream dimensionless seabed shear stress, θ, and Reynolds number, Re, on: (1) the maximum dimensionless seabed shear stress beneath the pipe, θmax, to be compared to the critical shear stress in order to determine whether scour would occur and progress towards an equilibrium state; and, (2) the dimensionless equilibrium scour depth beneath the pipe, Seq/D. Using a 2-D Reynolds averaged Navier-Stokes (RANS) approach along with the k-ω Shear Stress Transport (SST) turbulence model, a parametric study involving 243 computational fluid dynamics (CFD) simulations was conducted. The simulation results were used to develop a closed-form equation for the prediction of θmax. Subsequently, experimental measurements of Seq/D have been compiled from published literature, to develop a new closed-form equation for the prediction of Seq/D with a high correlation to the experimental data. In summary, we present two closed-form equations for the prediction of θmax and Seq/D for pipelines with an initial eo/D, which are applicable for both clear-water and live-bed conditions. The effects of θ and Re have been included, albeit Re having a small influence as compared to the other parameters.

Item Details

Item Type:Refereed Article
Keywords:maximum seabed shear stress, equilibrium scour depth, subsea pipelines, initial pipe elevation
Research Division:Engineering
Research Group:Maritime Engineering
Research Field:Ocean Engineering
Objective Division:Transport
Objective Group:Other Transport
Objective Field:Pipeline Transport
UTAS Author:Lee, JY (Mr Jun Lee)
UTAS Author:Hardjanto, FA (Dr Fauzi Hardjanto)
UTAS Author:Chai, S (Professor Shuhong Chai)
UTAS Author:Leong, ZQ (Dr Zhi Leong)
UTAS Author:Forrest, AL (Dr Alexander Forrest)
ID Code:129239
Year Published:2019
Deposited By:NC Maritime Engineering and Hydrodynamics
Deposited On:2018-11-17
Last Modified:2019-04-16
Downloads:0

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