Showing papers in "Ocean Engineering in 1988"

TL;DR: In this paper, the linearized hydrodynamic forces acting on a bottomless cylindrical body having vertical symmetry axis and oscillating in water of finite depth were dealt with, where the flow field around the structure was subdivided into ring-shaped fluid regions, in each of which an axisymmetric eigenfunction expansion for the velocity potential was made.

TL;DR: In this paper, the hydrodynamic interactions due to wave scattering between the numbers of an array of stationary, truncated circular cylinders simulating the columns of an idealized tension-leg platform (TLP) are investigated.

TL;DR: In this paper, the motion of a moored semi-submersible is modelled using a semi-empirical nonlinear ordinary differential equation, and the importance of nonlinearities is emphasised together with the implications for floating structures in general.

TL;DR: In this article, a method is presented for the numerical simulation of the three-dimensional geometric behavior of cable-towed acoustic array systems (as well as other series-connected marine structures).

TL;DR: In this paper, a simple geometrical model for generating the spray due to ship-wave collisions has been applied to determine the maximum height of the spray source above the ship deck.

TL;DR: In this paper, the diffraction of small-amplitude surface waves by floating and submerged stationary elliptical breakwaters in water of arbitrary uniform depth is investigated analytically, and the theoretical formulation leads to solutions for the fluid velocity potential in terms of series of Mathieu and modified Mathieu functions of real argument.

TL;DR: In this article, the authors brought together and extended previously known results for the added masses and dampings of surface-piercing or completely submerged horizontal circular cylinders, showing that a qualitative change occurs in these hydrodynamic coefficients when the cylinder breaks the surface.

TL;DR: The work of compiling the recently published book called Global Wave Statistics involved analysis of the statistical relationships between waves and winds on a worldwide basis as discussed by the authors, and some aspects of this experience not reported in the book, which it is believed should be of interest to ocean engineers and naval architects.

TL;DR: In this article, the sensitivity of heave response predictions for long riserless drill strings hanging from a floating vessel is examined. But the analysis is limited to the case of very long drill string systems, which can include a large package to be lowered to the seafloor.

TL;DR: In this paper, the influence of the scale effect in tow model and barge resistance has been investigated and it was shown that scale effect can cause the model barge to appear more course stable than the full scale barge.

TL;DR: In this paper, the effect of changes in sea state, as measured by the significant wave heigh H s, on the joint distribution of individual wave height and period are considered.

TL;DR: In this paper, a model for estimating the probability of vessel capsize in steep and high waves from the side in open sea and coastal waters is presented, which combines results from deterministic, single-wave model experiments and the estimation of probability of occurence of high waves for given sea states.

TL;DR: In this paper, the wave-exciting and motion-induced hydrodynamic forces for fixed and floating ocean structures in a fluid of finite or infinite depth were determined by means of a Helmholtz integral, which involves the normal fluid velocities at the fluid-structure interface.

TL;DR: In this article, the authors investigated the viscous damping force acting on a moored floating structure undergoing the slow-drift oscillation in irregular waves and found that the drag coefficients of a vertical cylinder oscillating with low frequencies in waves are quite different from those of a still water.

TL;DR: In this paper, the potential accuracy of local models is investigated to determine the mean direction of waves from the time history of locally observed significant wave height and locally observed wind. And the model results are also compared with results of two synoptic models which require large scale wind information to estimate the local mean wave direction.

TL;DR: In this paper, the authors compared the performance of vortex tube assist to the conventional environmental control system for habitat environmental control with substantial power savings, incorporating a complete description of psychrometric properties of the humid gas mixture within the habitat, as well as the sensible and latent heat loads associated with the occupants and wet porch of the habitat.

TL;DR: In this article, the eigen value problem describing the transverse vibration of a propeller-tail shaft system in two perpendicular planes is formulated modelling the propeller as a rotor.

TL;DR: In this paper, an experimental investigation has been carried out on forces induced by regular and random waves on submarine pipelines placed near a plane boundary and the inline and transverse forces are analyzed in terms of combined root mean square (rms) hydrodynamic coefficient.

TL;DR: In this article, the free vibration and the dynamic analyses for studying the response of a fixed offshore tower have been performed by using four different models of the same by idealising it as a frame as well as a truss.

TL;DR: In this article, the basic principles of the Bayesian method for drawing inferences are outlined step-by-step, and how Bayesian estimators of return values for wave heights are established by taking an expectation over all parameters and contending distributions.

TL;DR: This paper presents requisite documentation for linear arrays, and shows that Esteva's array can be used to advantage over the entire design range, and for simulated sinusoidal wave trains, analysis of both linear and polygonal arrays consistently yielded directions accurately, within ±1 degree in case of polygonAL arrays.

TL;DR: In this paper, the modification of the wave number spectra by currents that vary across the direction of flow is examined and a simple wave blocking model is employed to calculate energy dissipation by wave breaking.

TL;DR: The limitations imposed on the model structure due to the usage of model laws and the methods adopted to overcome the same are discussed in this paper, where the probable candidate materials for the modelling for experimentation is also highlighted.

TL;DR: In this paper, the authors present an analysis of the impact forces on a planing hull when it impacts on a flat water surface at an arbitrary speed and trim angle, and the results have little resemblance to any of the eight empirical approaches.

TL;DR: In this article, a numerical time simulation method is described to solve fluid flow problems including unsteady free surface motion, which is based on potential flow theory, and the problem is solved using a boundary integral formulation of the fluid domain.

TL;DR: In this paper, the authors present a simple method for calculating the hydrodynamic inertia and damping factors, based on the solution for the infinite "dry plate" at local vibratory loading.

TL;DR: In this paper, two methods are presented for analysis of second-order waves in a wave tank, by placing three wave probes in a line parallel to the line of propagation of long-crested irregular waves.

TL;DR: In this paper, the authors measured the increased steady drag on cylinders which vibrate due to flow-induced periodic forces in cross flows and identified geometric factors and flow characteristics which affect lock-in or wake capture.

TL;DR: In this paper, the influence of a square base placed at the bottom of a vertical cylinder on the wave induced forces and pressures on the cylinder is reported, and the experimental results are compared with MacCamy and Fuchs' theory.

TL;DR: In this article, a relationship between the transmission coefficient (determined by wave height and wave period) and a breakwater height above mean water level normalized with the height of wave run up measured directly by capacity wave meter is reported.