Predicting scour beneath subsea pipelines from existing small free span depths under steady currents
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...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2017-06-01
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| Series: | Journal of Ocean Engineering and Science |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2468013316300584 |
| _version_ | 1811228905026093056 |
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| author | Jun Y. Lee Jasmin McInerney Remo Cossu Zhi Q. Leong Alexander L. Forrest |
| author_facet | Jun Y. Lee Jasmin McInerney Remo Cossu Zhi Q. Leong Alexander L. Forrest |
| author_sort | Jun Y. Lee |
| collection | DOAJ |
| description | 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. |
| first_indexed | 2024-04-12T10:04:25Z |
| format | Article |
| id | doaj.art-8f97b5d2c4ee4269a2077422bae27be8 |
| institution | Directory Open Access Journal |
| issn | 2468-0133 |
| language | English |
| last_indexed | 2024-04-12T10:04:25Z |
| publishDate | 2017-06-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Ocean Engineering and Science |
| spelling | doaj.art-8f97b5d2c4ee4269a2077422bae27be82022-12-22T03:37:28ZengElsevierJournal of Ocean Engineering and Science2468-01332017-06-0122617510.1016/j.joes.2017.03.001Predicting scour beneath subsea pipelines from existing small free span depths under steady currentsJun Y. Lee0Jasmin McInerney1Remo Cossu2Zhi Q. Leong3Alexander L. Forrest4National Centre for Maritime Engineering and Hydrodynamics, Australian Maritime College, University of Tasmania, 1 Maritime Way, Newnham Tasmania 7248, AustraliaDepartment of Civil and Environmental Engineering, University of California – Davis, 1 Shields Avenue, Davis, CA 95616, United States of AmericaSchool of Civil Engineering, University of Queensland, St Lucia Queensland 4072, AustraliaNational Centre for Maritime Engineering and Hydrodynamics, Australian Maritime College, University of Tasmania, 1 Maritime Way, Newnham Tasmania 7248, AustraliaDepartment of Civil and Environmental Engineering, University of California – Davis, 1 Shields Avenue, Davis, CA 95616, United States of AmericaAn 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.http://www.sciencedirect.com/science/article/pii/S2468013316300584Sediment scourSubsea pipelinesSmall span depthsSteady currents |
| spellingShingle | Jun Y. Lee Jasmin McInerney Remo Cossu Zhi Q. Leong Alexander L. Forrest Predicting scour beneath subsea pipelines from existing small free span depths under steady currents Journal of Ocean Engineering and Science Sediment scour Subsea pipelines Small span depths Steady currents |
| title | Predicting scour beneath subsea pipelines from existing small free span depths under steady currents |
| title_full | Predicting scour beneath subsea pipelines from existing small free span depths under steady currents |
| title_fullStr | Predicting scour beneath subsea pipelines from existing small free span depths under steady currents |
| title_full_unstemmed | Predicting scour beneath subsea pipelines from existing small free span depths under steady currents |
| title_short | Predicting scour beneath subsea pipelines from existing small free span depths under steady currents |
| title_sort | predicting scour beneath subsea pipelines from existing small free span depths under steady currents |
| topic | Sediment scour Subsea pipelines Small span depths Steady currents |
| url | http://www.sciencedirect.com/science/article/pii/S2468013316300584 |
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