Showing papers in "Applied Ocean Research in 1994"

TL;DR: In this paper, the linearized frequency-domain analysis of wave radiation and diffraction by a three-dimensional body in a fixed mean position is extended to a variety of deformable body motions.

TL;DR: In this article, two approaches are used to analyze the two-dimensional nonlinear time domain free surface flow problem by the finite element method, one is based on the velocity potential which is approximated by means of shape functions, and the other approach is to write both potential and velocity in terms of the shape functions at the same time.

TL;DR: In this article, the authors examined the directional resolving power of various directional instruments and concluded that pitch/roll buoys have intrinsically poor resolving power and that improved instrument performance can be achieved by increasing the number of measurement elements in the measurement system.

TL;DR: In this article, the scattering of regular surface water waves by a single, flat, submerged plate is extended to consider the scattering by submerged, curved plates and also by surface-piercing, flat plates.

TL;DR: A review of the research carried out at the University of Michigan and elsewhere on the use of time-domain panel methods to compute the hydrodynamic forces acting on floating bodies and fully nonlinear computational techniques are presented.

TL;DR: In this article, a brief review is given of existing theory concerned with rigid-body device arrays and some new calculations presented for arrays able to absorb power through heave or surge motions, among the points considered are the improvement of performance from the unequal spacing of devices and the effects of constraining the amplitudes of device motions.

TL;DR: In this article, data acquired by the GEOSAT radar altimeter is used to determine mean monthly significant wave height climatologies for the globe and significant wave heights that could be expected to be exceeded at different percentage levels (exceedence probability) are presented.

TL;DR: In this article, numerical Fourier solutions for time-dependent two-dimensional standing gravity waves of finite amplitude in water of uniform depth are presented, while using a truncated double Fourier series for the velocity potential.

TL;DR: In this article, a special class of bivariate probability distributions with given (prespecified) marginals is studied, and a special member of this class, the Plackett model, is applied to represent the joint probability distribution of significant wave height and mean zero-upcrossing period (T 02 ).

TL;DR: In this paper, an appropriate one-term Galerkin approximation is used to evaluate very accurate upper and lower bounds for the reflection and transmission coefficients in the problems of oblique water wave diffraction by a thin vertical barrier present in water of uniform finite depth.

TL;DR: In this paper, the amplitude of the individual harmonics are determined by a least square fit to the non-linear free surface boundary conditions, which can be used to predict the kinematics beneath a recorded (or predicted) water surface elevation.

TL;DR: In this article, an efficient numerical scheme is proposed which retains the water-surface elevations in an implicit form in the governing equations, rather than using a series approximation, thus improving the accuracy of the numerical results.

TL;DR: An analytical solution of the two-dimensional linearised hydrodynamic problem is introduced based on the eigenfunction expansion technique in this article, where the breakwaters are assumed to be thin, impermeable, flexible and situated in an arbitrary water depth subjected to normal monochromatic waves.

TL;DR: In this article, the second-order difference-frequency inertia force is obtained from the complete description of the secondorder acceleration field, which includes both temporal and convective terms, and the resulting explicit force quadratic transfer functions (QTFs) are obtained for both uni-and multi-directional waves.

TL;DR: In this paper, a numerical model based on using a tank Green function was developed to compute the side wall effects on first and second-order loadings upon bodies of arbitrary geometry in wave tanks.

TL;DR: In this article, the Fourier-Galerkin model was extended to conformally-mapped domains with impermeable lateral boundaries and a Chebyshev-tau model for conformal domains was developed.

TL;DR: In this paper, a solution for the wave induced drift forces acting on a submerged sphere in a finite water depth based on linearised velocity potential theory is presented, where use has been made of multipole expansions in terms of an infinite series of Legendre functions with unknown coefficients.

TL;DR: In this paper, the authors extended the linear theory for waves impinging obliquely on vertical thin barriers to evaluate the scattering of irregular waves, described by a TMA directional wave spectrum.

TL;DR: In this article, a probabilistic model for the collision between a pair of cylinders in tandem subjected to random waves is presented and compared to experimental data, which is developed by adapting first-passage time formulations from Probabilistic mechanics and is extended to account for a non-Gaussian collision process by applying a Hermite transformation technique.

TL;DR: In this article, the relationship between frequency and wavelength for waves travelling on a sheared current has been explored in a laboratory flume, and measured changes in wavenumber due to positive and negative shears (shear is created upstream of the wavemaker by curved screens) agree with the dispersion relation described by J. Miles.

TL;DR: In this article, a hybrid numerical-analytical method is developed for the evaluation of the second-order velocity potential associated with bichromatic incident waves attacking a floating long horizontal cylinder of arbitrary cross-section, in water of finite depth.

TL;DR: In this article, a new technique for the generation of transient wave packets is proposed, which has been successfully tried on ship models in a towing tank, moving or stationary, with very good results.

TL;DR: In this paper, a statistical quadratization method was proposed to study the effect of nonlinear drag loading on the response statistics of a jack-up platform in deeper water, and the response kurtosis was also estimated using the statistical quadratic method.

TL;DR: In this article, a method for constructing the second-order diffraction potential associated with two-dimensional bodies is described, where analytic functions such as the square of the first-order complex velocity and taking their real or imaginary parts, harmonic functions are generated which are products of firstorder quantities.

TL;DR: In this article, the effects of cooling water discharge from a coastal power plant on underwater light levels using 6 years of integrated hourly irradiance measurements which were taken at the sea bottom in water depths of 10-14m.

TL;DR: In this article, the forced horizontal oscillations of a vertical cylinder extending throughout the fluid depth are considered on the basis of the linearised theory of water waves, and a new integral form is given for the frequency-domain solution and the procedure is then used to obtain an explicit timedomain solution.

TL;DR: In this paper, a perforated-ball velocity meter was developed for measuring three-dimensional velocities in laboratory waves and other flows, consisting of two small perforation balls which have well-defined Morison drag and inertia coefficients.

TL;DR: In this article, the 2nd and 4th order moments of the probability density function of an offshore structure are estimated using a small number of point loads, which is not enough for adequate representation of the continuous loading on (complex) structures with many structural elements.

TL;DR: In this paper, various techniques are used to predict the response probability density function (pdf) and mean up-crossing rate of a non-linearly moored vessel subject to combined first and second order wave forces.

TL;DR: In this article, a rational procedure for characterization of water depths, shallow or deep, for a random sea state is developed, in context with linearized wave theory, in which the filter coefficients are obtained as functions of the propagation distance which is normalized by the local water depth.