Visualization Tests on Scour Rates below Pipelines in Steady Currents
Publication: Journal of Hydraulic Engineering
Volume 145, Issue 4
Abstract
This paper presents visible experimental results of three-dimensional scour beneath pipelines. A miniature camera installed inside a transparent pipeline was used to observe the scour propagation process under a pipeline in steady currents. The data showed that the average scour hole propagation rate decreased nonlinearly with increasing pipeline embedment. The scour propagation rate increased with the Froude number at an increasing climb rate. The critical flow velocity for scour propagation was investigated. The critical velocity increased with increased pipeline embedment and the flow depth. It was lower than the critical velocity of sediment incipient motion. An empirical equation for the variation of the Froude number with the scour propagation rate was proposed for pipeline embedment ratios and relative flow depths .
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
This work was supported in part by the Chinese National Natural Science Foundation Council under Grant Nos. 11172213 and 51479137. The first author acknowledges the support from the China Scholarship Council (Grant No. 201806260166). Tsun-ming Wong and Ting Lin, two undergraduate students from the College of Civil Engineering, Tongji University, also contributed to the experiments.
References
An, H., L. Cheng, M. Zhao, G. Tang, and S. Draper. 2016a. “Detecting scour and liquefaction using OBS sensors.” In Proc., 8th Int. Conf. on Scour and Erosion, 535–542. Boca Raton, FL: CRC Press.
An, H., W. Yao, L. Cheng, S. Draper, M. Zhao, G. Tang, Y. Zhang, and P. Hortin. 2016b. “Detecting local scour using contact image sensors.” J. Hydraul. Eng. 143 (4): 04016100. https://doi.org/10.1061/(ASCE)HY.1943-7900.0001266.
Azamathulla, H., and A. Ghani. 2010. “Genetic programming to predict river pipeline scour.” J. Pipeline Syst. Eng. Pract. 1 (3): 127–132. https://doi.org/10.1061/(ASCE)PS.1949-1204.0000060.
Cheng, L., K. Yeow, Z. Zang, and F. Li. 2014. “3D scour below pipelines under waves and combined waves and currents” Coastal Eng. 83 (Jan): 137–149. https://doi.org/10.1016/j.coastaleng.2013.10.006.
Cheng, L., K. Yeow, Z. Zhang, and B. Teng. 2009. “Three-dimensional scour below offshore pipelines in steady currents” Coastal Eng. 56 (5–6): 577–590. https://doi.org/10.1016/j.coastaleng.2008.12.004.
Chiew, Y. 1990. “Mechanics of local scour around submarine pipelines.” J. Hydraul. Eng. 116 (4): 515–529. https://doi.org/10.1061/(ASCE)0733-9429(1990)116:4(515).
Chiew, Y. 1991. “Prediction of maximum scour depth at submarine pipelines.” J. Hydraul. Eng. 117 (4): 452–466. https://doi.org/10.1061/(ASCE)0733-9429(1991)117:4(452).
Dogan, M., and Y. Arisoy. 2015. “Scour regime effects on the time scale of wave scour below submerged pipes.” Ocean Eng. 104: 673–679. https://doi.org/10.1016/j.oceaneng.2015.06.010.
Fredsøe, J., B. M. Sumer, and M. Arnskov. 1992. “Time scale for wave/current scour below pipelines.” Int. J. Offshore Polar Eng. 2 (1): 13–17.
Guan, D., B. W. Melville, and H. Friedrich. 2015. “Live-bed scour at submerged weirs.” J. Hydraul. Eng. 141 (2): 04014071. https://doi.org/10.1061/(ASCE)HY.1943-7900.0000954.
Hansen, E. A., C. Staub, J. Fredsøe, and B. M. Sumer. 1991. “ Time-development of scour induced free spans of pipelines.” In Proc., 10th Conf. on Offshore Mechanics and Arctic Engineering, Pipeline Technology, 25–31. New York: ASME.
Liang, D., and L. Cheng. 2005. “Numerical modeling of flow and scour below a pipeline in currents: Part I. Flow simulation.” Coastal Eng. 52 (1): 25–42. https://doi.org/10.1016/j.coastaleng.2004.09.002.
McGovern, D. J., S. Ilic, A. M. Folkard, S. J. McLelland, and B. J. Murphy. 2014. “Time development of scour around a cylinder in simulated tidal currents.” J. Hydraul. Eng. 140 (6): 04014014. https://doi.org/10.1061/(ASCE)HY.1943-7900.0000857.
Moncada-M, A. T., and J. Aguirre-Pe. 1999. “Scour below pipeline in river crossings” J. Hydraul. Eng. 125 (9): 953–958. https://doi.org/10.1061/(ASCE)0733-9429(1999)125:9(953).
Postacchini, M., and M. Brocchini. 2015. “Scour depth under pipelines placed on weakly cohesive soils.” Appl. Ocean Res. 52: 73–79. https://doi.org/10.1016/j.apor.2015.04.010.
Qi, W., and F. Gao. 2014. “Physical modeling of local scour development around a large-diameter monopile in combined waves and current.” Coastal Eng. 83: 72–81. https://doi.org/10.1016/j.coastaleng.2013.10.007.
Sumer, B. M., and J. Fredsøe. 1991. “Onset of scour below a pipeline exposed to waves.” Int. J. Offshore Polar Eng. 1 (3): 189–194.
Sumer, B. M., and J. Fredsøe. 1992. “A review of wave/current-induced scour around pipelines.” In Proc., 23rd Int. Conf. on Coastal Engineering, 2839–2852. Reston, VA: ASCE.
Sumer, B. M., C. Truelsen, T. Sichmann, and J. Fredsoe. 2001. “Onset of scour below pipelines and self-burial.” Coastal Eng. 42 (4): 313–335. https://doi.org/10.1016/S0378-3839(00)00066-1.
Wu, Y., and Y. Chiew. 2012. “Three-dimensional scour at submarine pipelines.” J. Hydraul. Eng. 138 (9): 788–795. https://doi.org/10.1061/(ASCE)HY.1943-7900.0000583.
Wu, Y., and Y. Chiew. 2013. “Mechanics of three-dimensional pipeline scour in unidirectional steady current.” J. Pipeline Syst. Eng. Pract. 4 (1): 3–10. https://doi.org/10.1061/(ASCE)PS.1949-1204.0000118.
Zang, Z., L. Cheng, M. Zhao, D. Liang, and B. Teng. 2009. “A numerical model for onset of scour below offshore pipelines.” Coastal Eng. 56 (4): 458–466. https://doi.org/10.1016/j.coastaleng.2008.10.001.
Zhang, Q., S. Draper, and L. Cheng. 2016. “Scour below a subsea pipeline in time varying flow conditions.” Appl. Ocean Res. 55: 151–162. https://doi.org/10.1016/j.apor.2015.10.003.
Zhu, Y., L. Xie, and X. Liang. 2016. “Scour patterns below pipelines and scour hole expansion rate.” In Scour and Erosion: Proc., 8th Int. Conf. on Scour and Erosion, 387–394. Boca Raton, FL: CRC Press.
Information & Authors
Information
Published In
Copyright
©2019 American Society of Civil Engineers.
History
Received: Jun 26, 2018
Accepted: Sep 12, 2018
Published online: Jan 21, 2019
Published in print: Apr 1, 2019
Discussion open until: Jun 21, 2019
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.