Experimental Study of Local Scour around Twin Piles in Oscillatory Flows
Publication: Journal of Waterway, Port, Coastal, and Ocean Engineering
Volume 139, Issue 5
Abstract
Laboratory experiments have been carried out to investigate the scour around single piles and twin-pile groups subject to oscillatory flows. The Keulegan-Carpenter number, which is proportional to the ratio between the maximum excursion of water particles and the pile diameter, ranges from 3 to 110 in the experiments. To verify the experimental setup, the scour around a tall monopile was first studied, and the results were found to agree well with the previous research. The effect of the pile height and the influence of the twin-pile layout on the scour have been subsequently investigated. It was found that the scour became independent of the pile height once the pile was four times higher than the diameter. An empirical expression was constructed to describe the exponential variation of the scour depth with the pile height. The individual piles in a twin-pile group were found to behave independently when the separation was three times greater than the pile diameter. The relationships between the scour depths around the twin-pile groups and the group configuration were established graphically.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
D. Liang appreciates the support by the Matsumae International Foundation (MIF) during his visit to Kyoto University in 2012. H. Tang thanks the China National Funds for Distinguished Young Scientists (51125034) for financial support.
References
Angus, N. M., and Moore, R. L. (1982). “Scour repair methods in the southern North Sea.” Proc., 14th Annual Offshore Technology Conf., Offshore Technology Conf. (OTC), Houston, 385–399.
Baker, C. J. (1985). “The position of points of maximum and minimum shear stress upstream of cylinders mounted normal to flat plates.” J. Wind Eng. Ind. Aerodyn., 18(3), 263–274.
Bayram, A., and Larson, M. (2000). “Analysis of scour around a group of vertical piles in the field.” J. Waterway, Port, Coastal, Ocean Eng., 126(4), 215–220.
Dey, S., Rajkumar, R. V., and Abhishek, R. (2008). “Scour at submerged cylindrical obstacles under steady flow.” J. Hydraul. Eng., 134(1), 105–109.
Fredsøe, J., and Deigaard, R. (1992). Mechanics of coastal sediment transport, World Scientific, Singapore.
Herbich, J. B. (1981). “Scour around pipelines and other objects.” Chapter 3, Offshore pipeline design elements, Marcell Dekker, New York, 43–73.
Herbich, J. B., Schiller, R. E., Watanabe, R. K., and Dunlap, W. A. (1984). Seafloor scour: Design guidelines for ocean founded structures, Marcell Dekker, New York.
Mory, M., Larroude, P., Carreiras, J., and Seabra Santos, F. (2000). “Scour around pile groups.” Proc., Coastal Structures, Vol. 2, Balkema, Rotterdam, Netherlands, 773–781.
Myrhaug, D., and Rue, H. (2005). “Scour around group of slender vertical piles in random waves.” Appl. Ocean Res., 27(1), 56–63.
Niedoroda, A. W., and Dalton, C. (1982). “A review of the fluid mechanics of ocean scour.” Ocean Eng., 9(2), 159–170.
Nielsen, P. (1992). Coastal bottom boundary layers and sediment transport, World Scientific, Singapore.
Scott, N. (2011). “Wave scour around vertical piles.” M.S. thesis, Univ. of Cambridge, Cambridge, U.K.
Sumer, B. M., and Fredsøe, J. (1998). “Wave scour around group of vertical piles.” J. Waterway, Port, Coastal, Ocean Eng., 124(5), 248–256.
Sumer, B. M., and Fredsøe, J. (1999). “Wave scour around structures.” Chapter 5, Advances in coastal and ocean engineering, Liu P. L.-F., ed., World Scientific, Singapore, 191–249.
Sumer, B. M., and Fredsøe, J. (2002). The mechanics of scour in the marine environment, World Scientific, Singapore.
Sumer, B. M., Fredsøe, J., and Christiansen, N. (1992). “Scour around vertical pile in waves.” J. Waterway, Port, Coastal, Ocean Eng., 118(1), 15–31.
Sumner, D., Price, S. J., and Paidoussis, M. P. (2000). “Flow-pattern identification for two staggered circular cylinders in cross-flow.” J. Fluid Mech., 411, 263–303.
Woodwark, J. N. (2012). “Study on flow and scour around offshore structures.” M.S. thesis, Univ. of Cambridge, Cambridge, U.K.
Zhao, M., Cheng, L., and Zeng, Z. (2010). “Experimental and numerical investigation of local scour around a submerged vertical circular cylinder in steady currents.” Coastal Eng., 57(8), 709–721.
Information & Authors
Information
Published In
Journal of Waterway, Port, Coastal, and Ocean Engineering
Volume 139 • Issue 5 • September 2013
Pages: 404 - 412
Copyright
© 2013 American Society of Civil Engineers.
History
Received: Jul 4, 2012
Accepted: Dec 27, 2012
Published online: Dec 29, 2012
Published in print: Sep 1, 2013
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.