Determination of the Heave and Pitch Motions of a Floating Cylinder by Analytical Solution of its Diffraction Problem and Examination of the Effects of Geometric Parameters on its Dynamics in Regular Waves
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Abstract
In this paper, diffraction problem of a floating vertical circular cylinder is studied. Detailed analytical solution for the boundary value problem to evaluate the wave loads for the cylinder with heave and pitch motions in water of finite depth in the presence of an incident wave, has been presented. Accordingly, diffraction problem for a truncated vertical circular cylinder of radius in water of finite depth has been considered. Incident wave used in this problem, is assumed to be linear with amplitude . In order to calculate the added mass and damping coefficients of the pitch motion of the body, strip theory is applied. For the heave motion, the hydrodynamic coefficients are found by the submerged disk method. Parametric studies of the effects of the wave excitation force on the floating cylinder have been performed for two different cases: 1) constant draft of the cylinder with varying water depth and 2) varying draft of the cylinder with constant water depth.References
[1] Zheng, Y. H., Y. M. Shen, Y. G. You, B. J. Wu, and L. Rong,“Hydrodynamic properties of two vertical truncated cylinders in waves”, Ocean Engineering, Vol.32, (2005), pp. 241-271.
[2] Miles, J.W. and J.F. Gilbert, “Scattering of gravity waves by a circular dock”, Journal of Fluid Mechanics, Vol.34, (1968), pp. 783–793.
[3] Garret, C.J.R., “ Wave forces on a circular dock”, Journal of Fluid Mechanics, Cambridge, U.K., Vol.46, (1971), pp. 129-139.
[4] Black, J.L., C.C. Mei, and M.C.G. Bray, “Radiation and scattering of water waves by rigid bodies”, Journal of Fluid Mechanics, Vol.46, (1971), pp. 151–164.
[5] Isaacson, M.,”Wave forces on compound cylinders”, Proc. Civil Engineering in the Oceans IV, I, ASCE, San Francisco, (1979), pp. 518–530.
View more references (16)
[6] Yeung, R.W., “Added mass and damping of a vertical cylinder in finite-depth waters”, Applied Ocean Research, Vol.3, (1981), pp. 119–133.
[7] Sabuncu, T. and S. Calisal, “Hydrodynamic coefficients for vertical circular cylinders at finite depth”, Ocean Engineering, Vol.8, (1981), pp. 25–63.
[8] Calisal, S.M. and T. Sabuncu, “Hydrodynamic coefficients for vertical composite cylinders”, Ocean Engineering, Vol.11, (1984), pp. 529–542.
[9] Calisal, S.M. and T. Sabuncu, “A generalized method for the calculation of hydrodynamic forces on discontinuous vertical cylinders”, Ocean Engineering, Vol.20, (1993), pp. 1–18.
[10] Yeung, R.W. and S.H. Sphaier, “Wave-interference effects on a truncated cylinder in a channel”, Journal of Engineering Mathematics, Vol.23, (1989), pp. 95–117.
[11] Berggren, L. and M. Johansson, “Hydrodynamic coefficients of a wave energy device consisting of a buoy and a submerged plate”, Applied Ocean Research, Vol.14, (1992), pp. 51–58.
[12] Eidsmoen, H., “Hydrodynamic parameters for a two-body axisymmetric system”, Applied Ocean Research, Vol.17, (1995), pp. 103–115.
[13] Bhatta, D.D. and M. Rahman, “Wave loadings on a vertical cylinder due to heave motion”, International Journal of Mathematics and Mathematical Sciences, Vol.18, (1995), pp. 151-170.
[14] Bhatta, D.D. and M. Rahman, “On scattering and radiation problem for a cylinder in water of finite depth”, International Journal of Engineering Science, Vol.41, (2003), pp. 931–967.
[15] Williams, A.N. W. Li, and K.H. Wang, “Water wave interaction with a floating porous cylinder”, Ocean Engineering, Vol.27, (2000), pp. 1–28.
[16] Wu, B.J., Y.H. Zheng,Y.G. You, X.Y. Sun, and Y. Chen, “On diffraction and radiation problem for a cylinder over a caisson in water of finite depth”, International Journal of Engineering Science, Vol.42, (2004), pp.1193–1213.
[17] Huang, J.B. and R. Eatock Taylor, “Semi-analytical solution for second-order wave diffraction by a truncated circular cylinder in monochromatic waves”, Journal of Fluid Mechanics, Vol.319, (1996), pp. 171–196.
[18] Mavrakos, S.A. and I.K. Chatjigeorgiou, “Second-order hydrodynamic effects on an arrangement of two concentric truncated vertical cylinders”, Marine Structures, Vol.22, (2009), pp. 545–575.
[19] Mansouri, R. and H. Hadidi, “Comprehensive Study on the Linear Hydrodynamic Analysis of a Truss Spar in Random Waves”, World Academy of Science, Engineering and Technology, Vol.53, (2009), pp. 930-942.
[20] Patel, M.H., “Dynamics of Offshore Structures”, Butterworth-Heinemann, (1989), ISBN 0-408- 01074-6.
[21] Newman, J. N., “Marine Hydrodynamics”, (1977), MIT Press, Cambridge,UK.