Showing papers in "Applied Ocean Research in 1991"

TL;DR: In this article, an iterative solution procedure for solving the complete mild-slope wave (combined refractiondiffraction) equation is developed, which can be efficiently run in either the linear or nonlinear mode.

TL;DR: In this paper, the authors present both steady and transient analyses of the semi-empirical nonlinear differential equations which have been used to model the resonant rolling motions of two ships whose capsizes have been extensively discussed in the naval architecture literature.

TL;DR: In this paper, a semi-Wagner approach is used to compute the wetting factor and the Lagrange equations are employed to determine the slamming force from the kinetic energy of the fluid.

TL;DR: In this article, a simple dynamic model of a package suspended from a multi-cable configuration is presented, which is used as the basis to develop dimensionless curves which are useful for the preliminary assessment of the susceptibility of a design to snap load behavior.

TL;DR: In this paper, a time-domain second order method is developed to study the nonlinear wave forces and run upon a surface piercing body of arbitrary shape in two dimensions, and the free surface boundary conditions and the radiation condition are satisfied to second order by a numerical integration in time and the field solution at each time step is obtained by an integral equation method based on Green's theorem.

TL;DR: In this paper, a mathematical model for the lateral motion of a marine riser is developed to examine the effect of the internal flow and bending rigidity of the pipe on the dynamic behaviour of the riser.

TL;DR: In this article, the authors measured the pressure distributions on surface-piercing vertical cylinders due to breaking waves and found that the highest impact pressures are subject to considerable variability, including pressure oscillations, from run to run.

TL;DR: In this article, a scheme has been proposed for calculating first-order derivatives of wave-current-body interaction problem, which is one of the major difficulty in numerical solution of the problem.

TL;DR: In this article, an analytical model was developed for the dynamic analysis of an articulated loading platform (ALP) under regular wave excitations, and the dynamic response and stability of the ALP tower, treated as a single-degree-of-freedom system, was investigated with direct numerical integration and approximate analytical methods.

TL;DR: In this article, an equation for calculating two-dimensional second-order wave reflection and transmission coefficients is derived, which can be easily extended for calculating the free surface elevation at any points both in two-and three-dimensional cases.

TL;DR: In this paper, a power take-off mechanism for controlling the hydrodynamic response of a full scale oscillating water column (OWC) device is proposed, which consists of an air turbine, a float, and a hydraulic power conversion apparatus.

TL;DR: In this paper, the second-order sum frequency wave loads on the stationary ISSC Tension-Leg Platform (TLP) are obtained by the three-dimensional boundary integral equation method.

TL;DR: In this paper, the average duration of a run of high waves in groups and the average interval between such groups are significantly greater than the values found for general envelope crossings, since many large waves occur by themselves and not in groups.

TL;DR: In this article, a method for controlling a wave energy device to ensure high performance in random seas is presented, and a design proposed and analyzed for an oscillating water column device.

TL;DR: In this paper, matched asymptotic expansions are used to show that the added mass limits for the two cases differ by an amount that depends very simply on the geometry of the bodies.

TL;DR: In this paper, the authors investigated the interaction between a couple of sinusoidal undulations by means of a numerical method which is able to take into account the presence of the evanescent modes.

TL;DR: In this paper, the nonlinear free surface effects inside the oscillator, as well as a simplified model for nonlinear damping effects at the outlet, are introduced, and the solution of the problem is shown to be quite dependent on the non-linearities and shows response similar to a Duffing oscillator with a hardening spring.

TL;DR: In this article, a general formulation of water waves generated by an instantaneous axisymmetric free surface disturbance on an initially quiescent body of water is recalled, and the initial conditions characterizing the localized original disturbances are defined by the sum of a static departure of the free surface from the still water level and a free surface velocity distribution.

TL;DR: In this paper, the authors considered structural system reliability analysis when the spatial force pattern changes as the load increases, specifically when the nodal forces on a steel offshore jacket structure change as the base shear increases under increasing wave height.

TL;DR: In this article, a set of experiments has been performed with smooth and rough circular cylinders oscillating at small amplitudes and high frequencies, and it was shown experimentally that the attached flow region extends to higher Keulegan-Carpenter numbers in the high β case than in the low β case.

TL;DR: In this paper, a new correction procedure for Shipborne Wave Recorder (SBWR) wave height data is described, based on a new assessment of the available measurements of the frequency response of the SBWR using a Froude-type frequency scaling.

TL;DR: In this paper, a probabilistic wave spectrum was used to characterize a long-term random ocean wave by using a wave spectrum and an efficient and accurate method for estimating the fatigue damage of offshore structures was developed.

TL;DR: In this article, a theoretical and numerical approach to the dynamic behavior of drilling column (DC) in deep water under various exciting forces, due to seawater motion and drillship displacement allowing for possible collisions between DC-to-moonpool walls.

TL;DR: In this paper, a finite-infinite element method for solving the second order wave diffraction problem is presented, which is based on the inhomogeneous far field condition and its corresponding higher order asymptotic solutions for the second-order diffracted potential suggested by Li 9, and follows the finite-inverse element method as used by Lau and Ji 18.

TL;DR: In this article, the duality of constant stress and constant displacement-rate response of ice in uni-axial stress tests is used to infer a first order differential, non-linear viscoelastic, relation which describes qualitatively both responses through primary, secondary and tertiary creeps.

TL;DR: In this article, the Rankine Source Method is applied to the calculation of wave current interaction effects and a new radiation condition for unsteady flows is developed, which is equivalent to the artifice due to Rayleigh.

TL;DR: In this paper, a first order theory on the piston motion required to produce plane waves of small amplitude and a second order theory for eliminating the resonance of parasitic long waves in a circular basin is given.