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Experimental and numerical study of wave-induced backfilling beneath submarine pipelines
https://orcid.org/0000-0001-8892-1178
https://orcid.org/0000-0002-2433-6778
AbstractThis paper presents results of complementary experimental and numerical studies involving wave-induced backfilling of current-generated scour holes beneath submarine pipelines. The laboratory experiments are conducted in a wave-plus-current flume, utilizing Laser Doppler Anemometry to measure velocities, synchronized flow visualizations using digital image technology, along with live-bed scour and backfilling measurements. Each experiment is based on a two-stage process: (1) initial scour induced by a pure current, followed by: (2) backfilling induced by pure waves (either regular or irregular). The time series of scour depths are closely monitored through video recordings. Systematic analysis of these has resulted in a closed form expression for the backfilling time scale, which is demonstrated to be a full order of magnitude greater than the well-known time scale of scour (with both governed primarily by the Shields parameter). The developed expression is strictly valid for the current-to-wave backfilling scenarios considered, while likely serving as an upper limit for more general wave-induced backfilling circumstances. The experiments are complemented by similar backfilling simulations utilizing a fully-coupled hydrodynamic and morphodynamic CFD model. The numerical simulations demonstrate the ability of the model to predict backfilling towards expected equilibrium scour depths based on the new wave climate, with time scales reasonably in line with experimental expectations.
HighlightsWe study wave-induced backfilling of current-induced scour under submerged pipelines.Experiments with waves backfill to expected scour depths based on their KC numbers.The time scale of backfilling Tb is an order of magnitude larger than for scour.It can be estimated according to: Tb=0.3θ−5/3, where θ is the Shields parameter.Results from a fully-coupled CFD model generally support our experimental findings.
Experimental and numerical study of wave-induced backfilling beneath submarine pipelines
https://orcid.org/0000-0001-8892-1178
https://orcid.org/0000-0002-2433-6778
AbstractThis paper presents results of complementary experimental and numerical studies involving wave-induced backfilling of current-generated scour holes beneath submarine pipelines. The laboratory experiments are conducted in a wave-plus-current flume, utilizing Laser Doppler Anemometry to measure velocities, synchronized flow visualizations using digital image technology, along with live-bed scour and backfilling measurements. Each experiment is based on a two-stage process: (1) initial scour induced by a pure current, followed by: (2) backfilling induced by pure waves (either regular or irregular). The time series of scour depths are closely monitored through video recordings. Systematic analysis of these has resulted in a closed form expression for the backfilling time scale, which is demonstrated to be a full order of magnitude greater than the well-known time scale of scour (with both governed primarily by the Shields parameter). The developed expression is strictly valid for the current-to-wave backfilling scenarios considered, while likely serving as an upper limit for more general wave-induced backfilling circumstances. The experiments are complemented by similar backfilling simulations utilizing a fully-coupled hydrodynamic and morphodynamic CFD model. The numerical simulations demonstrate the ability of the model to predict backfilling towards expected equilibrium scour depths based on the new wave climate, with time scales reasonably in line with experimental expectations.
HighlightsWe study wave-induced backfilling of current-induced scour under submerged pipelines.Experiments with waves backfill to expected scour depths based on their KC numbers.The time scale of backfilling Tb is an order of magnitude larger than for scour.It can be estimated according to: Tb=0.3θ−5/3, where θ is the Shields parameter.Results from a fully-coupled CFD model generally support our experimental findings.
Experimental and numerical study of wave-induced backfilling beneath submarine pipelines
https://orcid.org/0000-0001-8892-1178
https://orcid.org/0000-0002-2433-6778
AbstractThis paper presents results of complementary experimental and numerical studies involving wave-induced backfilling of current-generated scour holes beneath submarine pipelines. The laboratory experiments are conducted in a wave-plus-current flume, utilizing Laser Doppler Anemometry to measure velocities, synchronized flow visualizations using digital image technology, along with live-bed scour and backfilling measurements. Each experiment is based on a two-stage process: (1) initial scour induced by a pure current, followed by: (2) backfilling induced by pure waves (either regular or irregular). The time series of scour depths are closely monitored through video recordings. Systematic analysis of these has resulted in a closed form expression for the backfilling time scale, which is demonstrated to be a full order of magnitude greater than the well-known time scale of scour (with both governed primarily by the Shields parameter). The developed expression is strictly valid for the current-to-wave backfilling scenarios considered, while likely serving as an upper limit for more general wave-induced backfilling circumstances. The experiments are complemented by similar backfilling simulations utilizing a fully-coupled hydrodynamic and morphodynamic CFD model. The numerical simulations demonstrate the ability of the model to predict backfilling towards expected equilibrium scour depths based on the new wave climate, with time scales reasonably in line with experimental expectations.
HighlightsWe study wave-induced backfilling of current-induced scour under submerged pipelines.Experiments with waves backfill to expected scour depths based on their KC numbers.The time scale of backfilling Tb is an order of magnitude larger than for scour.It can be estimated according to: Tb=0.3θ−5/3, where θ is the Shields parameter.Results from a fully-coupled CFD model generally support our experimental findings.
Experimental and numerical study of wave-induced backfilling beneath submarine pipelines
Bayraktar, Deniz (author) / Ahmad, Joseph (author) / Larsen, Bjarke Eltard (author) / Carstensen, Stefan (author) / Fuhrman, David R. (author)
Coastal Engineering ; 118 ; 63-75
2016-08-23
13 pages
Article (Journal)
Electronic Resource
English
Scour , Backfilling , Pipelines , Sediment transport , Time scale , Steady current , Waves
Experimental and numerical study of wave-induced backfilling beneath submarine pipelines
| British Library Online Contents | 2016
Experimental and numerical study of wave-induced backfilling beneath submarine pipelines
| Online Contents | 2016
Experimental and numerical study of wave-induced backfilling beneath submarine pipelines
| Online Contents | 2016
Numerical simulation of wave-induced scour and backfilling processes beneath submarine pipelines
| Online Contents | 2014