Nonlinear Hydrodynamics of a Floating Cylinder in Oscillatory Flow Alone and Combined with a Current
Publication: Journal of Waterway, Port, Coastal, and Ocean Engineering
Volume 143, Issue 2
Abstract
This paper experimentally investigates the nonlinear hydrodynamic forces on a semisubmerged floating collar under full-scale Reynolds number (R) and Keulegan-Carpenter number (KC) oscillatory flow alone and combined with a current. The collar was forced to oscillate harmonically in the direction of the current within a wide range of oscillation amplitudes and frequencies. The first five orders of the horizontal hydrodynamic forces are obtained using Fourier transformation techniques. The influence of the KC, the frequency parameter (), and the reduced velocity (Vr) on the high-order components of the hydrodynamic force were investigated. The results show that, under oscillatory flows, the first five harmonics of the hydrodynamic force coefficients increase with an increase of KC and . As the reduced velocity (Vr) increases, the first- and second-order components are greatly affected. These first two order components contribute greatly to the overall hydrodynamic force in the combined flow condition, with no apparent slamming, whereas the last three orders contribute less. The first two harmonics agree well with the experimental results when overtopping occurs; however, differences are apparent where slamming occurs.
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Acknowledgments
Support from the National Natural Science Foundation of China (Grants 51279101, 51490674, and 51490675) is greatly appreciated.
References
Blevins, R. D. (1990). Flow-induced vibration, Van Nostrand Reinhold Company, New York.
Chakrabarti, S. K. (1987). Hydrodynamics of offshore structures, WIT Press, Southampton, U.K.
Chen, B., Lu, L., Greated, C. A., and Kang, H. (2015). “Investigation of wave forces on partially submerged horizontal cylinders by numerical simulation.” Ocean Eng., 107, 23–31.
Endresen, P. C. (2011). “Vertical wave loads and response of a floating fish farm with circular collar.” Master’s thesis, Dept. of Marine Technology, NTNU, Trondheim, Norway.
Faltinsen, O. (1993). Sea loads on ships and offshore structures, Vol. 1, Cambridge Univ. Press, Cambridge, U.K., 191.
Faltinsen, O. M. (2011). “Hydrodynamic aspects of a floating fish farm with circular collar.” Proc., 26th Int. Workshop on Water Waves and Floating Bodies (IWWWFB), Athens, Greece, April 17–20.
Fu, S. X., and Moan, T. (2012). “Dynamic analyses of floating fish cage collars in waves.” Aquacult. Eng., 47, 7–15.
Fu, S. X., Xu, Y. W., Hu, K., and Zhang, Y. (2013). “Experimental investigation on hydrodynamics of floating cylinder in oscillatory and steady flows by forced oscillation test.” Mar. Struct., 34, 41–55.
Fu, S., Xu, Y., Hu, K., Zhong, Q., and Li, R. (2014). “Experimental investigation on hydrodynamics of a fish cage floater-net system in oscillatory and steady flows by forced oscillation tests.” J. Ship Res., 58(1), 20–29.
Kristiansen, D. (2010). “Wave induced effects on floaters of aquaculture plants.” Ph.D. thesis, Dept. of Marine Technology, NTNU, Trondheim, Norway.
Kristiansen, D., and Faltinsen, O. M. (2008). “A study of wave loads on fixed horizontal cylinders in the free surface.” Proc., 8th Int. Conf. on Hydrodynamics (ICHD), September, Nantes, France.
Li, P., and Faltinsen, O. M. (2012). “Wave induced response of an elastic circular collar of a floating fish farm.” Proc., 10th Int. Conf. on Hydrodynamics, Vol. 2, St. Petersburg, Russia, 58–64.
Li, Y. C., Gui, F. K., and Teng, B. (2007). “Hydrodynamic behavior of a straight floating pipe under wave conditions.” Ocean Eng., 34(3), 552–559.
Sarpkaya, T. (1976). “Vortex shedding and resistance in harmonic flow about smooth and rough circular cylinders at high Reynolds numbers.” Rep. NPS-59SL76021, Naval Postgraduate School, Monterey, CA.
Sarpkaya, T. (2010). Wave forces on offshore structures, Cambridge Univ. Press, New York.
Sumer, B. M., and Fredsøe, J. (1997). Hydrodynamics around cylindrical structures, World Scientific, Singapore, 93.
Thomassen, P. E. (2008). “Methods for dynamic response analysis and fatigue life estimation of floating fish cages.” Ph.D. thesis, Dept. of Marine Technology, NTNU, Trondheim, Norway.
WAMIT [Computer software]. Wamit, Inc., Chestnut Hill, MA.
Wang, J., Fu, S., Baarholm, R., Wu, J., and Larsen, C. M. (2015). “Fatigue damage induced by vortex-induced vibrations in oscillatory flow.” Mar. Struct., 40, 73–91.
Xu, T. J., Dong, G. H., Zhao, Y. P., Li, Y. C., and Gui, F. K. (2011). “Analysis of hydrodynamic behaviors of gravity net cage in irregular waves.” Ocean Eng., 38(13), 1545–1554.
Xu, T. J., Dong, G. H., Zhao, Y. P., Li, Y. C., and Gui, F. K. (2012). “Numerical investigation of the hydrodynamic behaviors of multiple net cages in waves.” Aquacult. Eng., 48, 6–18.
Xu, T. J., Zhao, Y. P., Dong, G. H., Li, Y. C., and Gui, F. K. (2013). “Analysis of hydrodynamic behaviors of multiple net cages in combined wave–current flow.” J. Fluids Struct., 39, 222–236.
Zhao, Y. P., Li, Y. C., Dong, G. H., and Gui, F. K. (2007a). “Numerical simulation of hydrodynamic behaviors of gravity cage in waves.” China Ocean Eng., 21(2), 225–238.
Zhao, Y. P., Li, Y. C., Dong, G. H., Gui, F. K., and Teng, B. (2007b). “Numerical simulation of the effects of structure size ratio and mesh type on three-dimensional deformation of the fishing-net gravity cage in current.” Aquacult. Eng., 36, 285–301.
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Published In
Journal of Waterway, Port, Coastal, and Ocean Engineering
Volume 143 • Issue 2 • March 2017
Copyright
© 2016 American Society of Civil Engineers.
History
Received: Sep 16, 2015
Accepted: May 25, 2016
Published online: Jul 28, 2016
Discussion open until: Dec 28, 2016
Published in print: Mar 1, 2017
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