Predicting scour beneath subsea pipelines from existing small free span depths under steady currents

Lee, Jun Y., McInerney, Jasmin, Cossu, Remo, Leong, Zhi Q. and Forrest, Alexander L. (2017) Predicting scour beneath subsea pipelines from existing small free span depths under steady currents. Journal of Ocean Engineering and Science, . doi:10.1016/j.joes.2017.03.001


Author Lee, Jun Y.
McInerney, Jasmin
Cossu, Remo
Leong, Zhi Q.
Forrest, Alexander L.
Title Predicting scour beneath subsea pipelines from existing small free span depths under steady currents
Journal name Journal of Ocean Engineering and Science
ISSN 2468-0133
Publication date 2017-03-18
Sub-type Article (original research)
DOI 10.1016/j.joes.2017.03.001
Open Access Status DOI
Total pages 51
Place of publication Shanghai, China
Publisher Shanghai Jiaotong University
Collection year 2018
Language eng
Abstract An equation was developed to predict current-induced scour beneath subsea pipelines in areas with small span depths, S. Current equations for scour prediction are only applicable to partially buried pipelines. The existence of small span depths (i.e. S/D < 0.3) are of concern because the capacity for scour is higher at smaller span depths. Furthermore, it is impractical to perform rectification works, such as installing grout bags, under a pipeline with a small S/D. Full-scale two-dimensional Computational Fluid Dynamics (CFD) simulations were performed using the Reynolds-averaged Navier–Stokes approach and the Shear Stress Transport k-ω turbulence model. To predict the occurrence of scour, the computed maximum bed shear stress beneath the pipe was converted to the dimensionless Shields parameter, and compared with the critical Shields parameter based on the mean sediment grain size. The numerical setup was verified, and a good agreement was found between model-scale CFD data and experimental data. Field data were obtained to determine the mean grain size, far field current velocity and to measure the span depths along the surveyed pipe length. A trend line equation was fitted to the full-scale CFD data, whereby the maximum Shields parameter beneath the pipe can be calculated based on the undisturbed Shields parameter and S/D.
Keyword Sediment scour
Subsea pipelines
Small span depths
Steady currents
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Civil Engineering Publications
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Created: Wed, 12 Apr 2017, 12:51:35 EST by Anthony Yeates on behalf of Learning and Research Services (UQ Library)