Wave loadings on a vertical cylinder due to heave motion

Abstract

ABSTRACT. Wave forces and moments due to scattering and radiation for a vertical circular cylinder heaving in water of finite depth are derived analytically. These are derived fi'om the total velocity potential which can be decomposed as two velocity potentials; one due to scattering in the presence of an incident wave on fixed structure (diffraction problem), and the other due to radiation by the heave motion on cahn water (radiation problem). For each part, the velocity potential is derived by considering two regions, namely, interior region and exterior region. The complex matrix equations are solved numerically to determine the unknown coefficients to compute the wave loads.Some numerical results are presented for different depth to radius and draft to radius ratios.

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

“…Governing equation for the potential in the interior region is as follows: (9) (10) (11) Using the method of separation of variables, the procedure of solving problem is performed as follows: (12) Substituting (12) in Laplace's equation (Eq.9): (13) Both sides of Eq.13 must equal the same constant whereas is assumed to be the arbitrary constant . Equation (13) yields in three ordinary differential equations:…”

“…Berggren and Johansson [11] and Eidsmoen [12] presented the heave radiation problem of a two-body axisymmetric system and calculated the heave added masses and damping coefficients. Bhatta and Rahman [13,14] calculated the analytical and numerical results for diffraction loads and radiation coefficients for a vertical circular cylinder in a finite water depth. Williams et al [15] studied the radiation and diffraction by a single floating circular cylinder and obtained theoretical results of hydrodynamic coefficients and the wave forces.…”

Modeling and control of a coupled electromechanical system exploiting heave motion, for energy conversion from sea waves

“…where M is an equivalent mass which incorporates the total inertial characteristics of the system and z is the displacement of the buoy [10].…”

An Analytical Solution of Wave Exciting Loads on CALM Buoy with Skirt

“…In order to calculate the wave exciting loads or hydrodynamics coefficients on any arbitrary shape structures in waves, it is necessary to use boundary element method [3] or finite element method [4][5] . For the offshore structures with idealized geometric shapes such as vertical truncated circular cylinder, the solution can be obtained by applying eigenfunction expansion approach [6][7][8][9] . An experimental study of wave interaction with a vertical truncated cylinder was carried out by Zhao et al [10] .…”