Morison coefficients for a circular cylinder oscillating with dual frequency in still water: an analysis using independent-flow form of Morison’s equation

Journal of Ocean Engineering and Marine Energy - Tập 1 - Trang 435-444 - 2015
Zhida Yuan1,2, Zhenhua Huang3
1School of Civil and Environmental Engineering, Nanyang Technological University, Singapore, Singapore
2Neptune Offshore Engineering Development Co., LTD, Tianjin China
3Department of Ocean and Resources Engineering, School of Ocean and Earth Science and Technology, University of Hawaii at Manoa, Honolulu, USA

Tóm tắt

In this study, a set of experimental results for wave forces acting on a cylinder oscillating with dual frequency in still water are reported. The experiment was designed to mimic a cylinder slowly oscillating in regular waves, with the high-frequency oscillation representing the wave motion and the low-frequency oscillation, the slow drift motion. The inline forces acting on the cylinder were analyzed using the independent-flow form of Morison’s equation. Our experimental results showed that it was not appropriate to simply use in the independent-flow form of Morison’s equation the added-mass and drag coefficients obtained for the cylinder oscillating with a single frequency in still water. A new dimensionless parameter was introduced to describe each of the wave force coefficients used in the independent-flow form of Morison’s equation, and empirical expressions for the wave force coefficients were proposed using the new dimensionless parameters.

Tài liệu tham khảo

Boccotti P, Arena F, Fiamma V, Barbaro G (2012) Field experiment on random wave forces acting on vertical cylinders. Probab Eng Mech 28:39–51 Boccotti P, Arena F, Fiamma V, Romolo A (2013) Two small-scale field experiments on the effectiveness of Morison’s equation. Ocean Eng 57:141–149 Burrows R, Tickell RG, Najafian G (1997) Morison wave force coefficients for application to random seas. Appl Ocean Res 19:183–199 Chakrabarti SK (1987) Hydrodynamics of offshore structures. WIT Press, Southampton, UK DNV (2010) Global performance analysis of deepwater floating structures. DNV-RP-F205, DET NORSKE VERITAS (DNV) Gudmestad OT, Connor JJ (1983) Linearization methods and the influence of current on the nonlinear hydrodynamic drag force. Appl Ocean Res 5(4):184–194 Koterayama W (1984) Wave forces acting on a vertical circular cylinder with a constant forward velocity. Ocean Eng 11(4):363–379 Koterayama W, Nakamura M (1988) Hydrodynamic forces acting on a vertical circular cylinder oscillating with a very low frequency in waves. Ocean Eng 15(3):271–287 Laya EJ, Cornnor JJ, Sunder SS (1984) Hydrodynamic forces on flexible offshore structures. J Eng Mech 110(3):433–448 Liu YG, Bergdahl L (1996) Frequency-domain dynamic analysis of cables. Eng Struct 19(6):499–506 Moe G, Verley RLP (1980) Hydrodynamic damping of offshore structures in waves and currents. In: Proceedings of the 12th annual offshore technology conference. Houston, pp 37–44 Najafian G, Burrows R, Tickell RG (1995) A review of the probabilistic description of Morison wave loading and response of fixed offshore structures. J Fluids Struct 9:585–616 Obasaju ED, Bearman PW, Graham JMR (1988) A study of forces, circulation and vortex patterns around a circular cylinder in oscillating flow. J Fluid Mech 196:467–494 Sarpkaya T, Storm M (1985) In-line force on a cylinder translating in oscillatory flow. Appl Ocean Res 7(4):188–196 Sarpkaya T (1986) Force on circular cylinder in viscous oscillatory flow at low Keulegan–Carpenter numbers. J Fluid Mech 65:61–71 Wolfram J, Naghipour M (1999) On the estimation of Morison force coefficients and their predictive accuracy for very rough circular cylinders. Appl Ocean Res 21:311–328 Yuan ZD, Huang ZH (2010) An experimental study of inertia and drag coefficients for a truncated circular cylinder in regular waves. J Hydrodyn 22(5):318–323 Yuan ZD, Huang ZH (2011) Hydrodynamic forces on a transverse oscillating circular cylinder in regular waves. In: Proceedings of the 21st international offshore and polar engineering conference. Maui, pp 1262–1269