Showing papers in "Ocean Engineering in 1994"

TL;DR: In this article, a numerical approach is presented which is capable of predicting the dynamic behaviour of three-dimensional marine cables, which is of practical importance in the estimation of dybamic loading and motion, and thus has direct application to the enhancement of safety and effectiveness of the offshore activities.

TL;DR: In this article, a theoretical investigation of wave interaction with a concentric surface-piercing two-cylinder system is presented, and the free-surface elevation and the total net hydrodynamic forces acting on both cylinders are determined analytically.

TL;DR: In this paper, a numerical model is developed to examine a global aspect of wave-induced porewater pressures and effective stresses in a sand seabed as well as those in a rubble mound foundation of a composite caisson-type breakwater and in rubble mound breakwater, where the Biot's consolidation equations are employed.

TL;DR: In this paper, the wave loads induced by short-crested incident waves on a vertical cylinder of arbitrary cross-section are discussed and it is shown that for a cylinder of a certain cross-sectional area, wave loads can be larger than those induced by plane waves with the same total wave number.

TL;DR: In this paper, the authors used the results of a series of drifting buoy experiments carried out in the Arabian Gulf during 1983-1984 to estimate wind-induced surface oil spill speed and the associated deflection angle.

TL;DR: In this paper, the longitudinal distribution of the non-linear component of the lateral force, the so-called cross-flow drag, is analyzed for a ship in a tight turn during which the ship's drift velocity becomes relatively large compared to the ahead speed.

TL;DR: In this paper, Zhao and Faltinsen showed that the added mass associated with the splashed-up water is not that of the intersection of the wedge with the undisturbed water surface, but the wetted width of splashed up water, as originally proposed by Wagner.

TL;DR: In this article, the eigenfunction expansion method is used to develop a theoretical solution for the flow field caused by monochromatic oblique waves incident upon an infinitely long, submerged, wide and vertical breakwater situated in arbitrary water depth.

TL;DR: In this article, a static analysis of the flexible riser under its self-weight and current is presented using a finite difference approach. The problem essentially involves geometrical nonlinearity, which is tackled with the help of an iterative solution based on modified Newton-Raphson technique.

TL;DR: In this paper, it was shown that the joint effect of Langmuir circulation and turbulence is to homogenize the oil concentration over the Stommel retention zone, and that when the buoyant rise speeds of oil droplets are much smaller than the downwelling velocity of the coherent cells, oil concentration will be uniformly distributed across whole cells.

TL;DR: In this article, a theoretical study of a breakwater-seawall wave-trapping system is presented, where the velocity potentials of the wave motion are coupled with the equation of motion of the breakwater.

TL;DR: The method of differential quadrature developed by Bellman in the 1970s has only recently been applied in the solution of technically important problems as mentioned in this paper, which consists, essentially, of the approximate solution of the differential system by means of a polynomial-collocation approach at a finite number of points selected by the analyst.

TL;DR: In this paper, an approximate semi-analytical technique was developed to calculate the wave-induced loads and added mass and radiation damping coefficients for idealized ocean structures consisting of arrays of large-diameter, truncated, vertical circular cylinders.

TL;DR: An improved algorithm is developed for predicting the transient response of a system of serially connected cables and bodies during unsteady deployment from a surface vessel by introducing a stable Newmark-like implicit integration scheme in time and by a direct integration method with suppression of extraneous erroneous solutions.

TL;DR: In this paper, it was shown that the optimum shape for a transatlantic, deep-diving, autonomous submersible is a low-drag hull shape with a displaced volume of 4.4 m 3, a length of 5.97 m and a maximum diameter of 1.33 m.

TL;DR: In this article, the coupling problem of a two-dimensional tension leg structure interacting with a monochromatic linear wave train has been solved analytically, and potential theory is utilized to facilitate the coupling of the interaction among waves, the large floating structure, and the small tension legs.

TL;DR: In this article, an approach described in this paper uses an approximate criterion for safe, forced, roll oscillations of a typical semi-submersible based on a stability margin.

TL;DR: In this article, the problem of oscillating viscous flow over a stationary cylinder of elliptic cross-section is investigated, where the free stream direction is always normal to the cylinder axis and oscillations are only allowed in the magnitude of the stream velocity.

TL;DR: In this paper, the eddy viscosities for the steady and the periodic components of combined wave-current flows have been studied quantitatively from the presently available experimental data, and it has been found that inside the boundary interaction layer [z δ] it is affected little by the wave motion.

TL;DR: In this article, a two-dimensional linear diffraction solution for submerged bodies of rectangular section is utilized to calculate the Froude-Krylov force coefficients for the case when the body is located close to the free-surface or sea-bed.

TL;DR: In this paper, a new orbital criterion is proposed to avoid the problem of false waves that alter the wave statistics of random sea waves, and the new criterion produces a distribution of wave heights in better agreement with the Rayleigh distribution.

TL;DR: In this paper, the authors present the application of the random decrement technique to nonlinear ship roll motion and the validity, accuracy and reliability of the method are investigated using model experimental and full-scale ship test data.

TL;DR: In this article, a test program was carried out by injecting lime into a soft marine clay in a test tank, which showed good promise for the use of lime grouting in the treatment of weak marine clayey deposits.

TL;DR: In this paper, the authors studied the problem of oscillating inviscid flow over an elliptic cylinder for various angles of attack, where the flow direction is always normal to the cylinder axis and oscillations are only allowed in the magnitude of the free stream velocity.

TL;DR: In this paper, an analytical theory describing the mass transport velocity induced by water waves in a turbulent boundary layer is presented, where a one-layer time-invariant eddy viscosity model is specified to calculate steady streaming within boundary layer.

TL;DR: In this article, the physicico-chemical changes that occurred in a marine clay with various inorganic additives are presented and discussed, and the improvement in the strength and plasticity characteristics of the soil have also been studied and reported.

TL;DR: In this article, three different barge sizes were tested in uniform current in a tank of limited width and the effect of the tank walls on the lateral forces on the barge was clearly shown.

TL;DR: In this article, the mineralogical studies of some Cochin marine clays were carried out using XRD technique and the physical and chemical properties of these clays are also reported.

TL;DR: In this article, the behavior of steel pipe piles under cyclic load was studied by conducting tests on model pipe piles in a soft marine clay, and it was found that when the cyclic loading level is low, the movements get stabilized within the first few hundred cycles of loading.