Wave-Body Interactions Among an Array of Truncated Vertical Cylinders

A semi-analytical method is developed to investigate water-wave radiation and diffraction by an array of truncated vertical cylinders as a model for a point-absorber wave farm. Each cylinder can have independent movements in six modes. The method of matched eigenfunction expansions is applied to obtain the velocity potential for the fluid. To achieve fast computation, the effects of evanescent modes of locally scattered waves from one cylinder are neglected in the near fields of the neighboring cylinders. Wave-exciting forces and moments on an individual cylinder or a group of cylinders, situated among an array, are evaluated by a new, generalized form of Haskind relation that is applicable to an array configuration. In results, hydrodynamic coefficients and wave-exciting loads are presented for arrays of different configurations. Comparisons between wave-exciting loads obtained from the generalized Haskind relation and those from direct diffraction solutions show excellent agreements.

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

Linearized potential wave theory is applied to calculate the wave exciting loads on a CALM buoy in water of finite depth. The solution is based on the domain decomposition method and the unknown constants in the velocity potentials are determined by matched eigenfunction expansions. A comparison of the analytical solution with published experimental results on a vertical truncated cylinder is performed as part of the validation process. The effects of the disk on the wave exciting forces are discussed.

Inertia, Damping, and Wave Excitation of Heaving Coaxial Cylinders

The method of matched eigenfunction expansions is applied in this paper to obtain the hydrodynamic coefficients of a pair of coaxial cylinders, each of which can have independent movement. The geometry idealizes a device for extracting ocean wave energy in the heave mode. The effects of geometric variations and the interaction between cylinders on the hydrodynamic properties are discussed. Analytical expressions for the low-frequency behavior of the hydrodynamic coefficients are also derived. The wave-exciting force on the bottom surface of either one of the cylinders is derived using the radiation solutions, with a generalized form of the Haskind relation developed for this geometry. The presented results are immediately applicable to examine free motion of coaxial cylinders in a wave field.

Sloshing in a Vertical Circular Cylindrical Container With a Vertical Baffle

The linear problem of liquid sloshing in a cylindrical container with a vertical baffle is considered in the present paper. In this study, a theoretical oriented approach is developed for calculating the natural frequencies of liquid. The baffle is a thin-walled and open-ended cylindrical shell that is concentrically placed and partially submerged inside the container. The free surface of liquid is assumed to be perpendicular to axis of the container and is divided into two parts by the baffle. The method also captures the singular asymptotic behavior of the velocity potential at the sharp baffle edge. The liquid is assumed to be incompressible and inviscid and the method uses matched eigenfunction expansions and Galerkin expansions to derive unknown coefficients presented in the velocity potential series. A finite element analysis is also used to check the validity of the proposed method. The effects of some important parameters of system are also considered on the sloshing frequencies.