Showing papers in "Coastal Engineering in 1995"

TL;DR: In this article, time-dependent measurements of flow velocities and sediment concentrations were conducted in a large oscillating water tunnel, aimed at the flow and sediment dynamics in and above an oscillatory boundary layer in plane bed and sheet-flow conditions.

TL;DR: In this paper, the characteristics of turbulence created by a plunging breaker on a 1 on 35 plane slope have been studied experimentally in a two-dimensional wave tank, and the results show that turbulence under a plungeding breaker is dominated by large-scale motions and has certain unique features that are associated with its wave condition.

TL;DR: In this article, the Navier-Stokes equation is applied as a basis for the derivations of porosity in coarse granular media with special concern given to the variation of the flow resistance with the porosity.

TL;DR: In this article, a linearized version of the Boussinesq equations corresponds to a higher order Pade expansion in the Stokes linear dispersion relation for waves on arbitrary depth.

TL;DR: In this article, a bispectral analysis of electromagnetic flow meter data collected from four nearshore environments was undertaken to investigate the spatial variation of velocity skewness and asymmetry for shoaling and breaking surface gravity waves.

TL;DR: In this article, the applicability of three different wave propagation models in nonlinear dispersive wave fields has been investigated, and the numerical models tested were based on three wave theories: a fully nonlinear potential theory, a Stokes second-order theory, and a Boussinesq-type theory with an improved dispersion relation.

TL;DR: In this article, a new method for separating an irregular, 2D wave field into incident waves propagating towards a structure and reflected wave propagating away from the structure is presented.

TL;DR: In this article, a study was undertaken to evaluate ten of the most well-known mathematical cross-shore sediment transport models with regard to different model requirements and the characteristics of these time-dependent models were investigated and the pros and cons of each are listed.

TL;DR: In this article, an analytical model is developed that can predict the reflection coefficient of a perforated-wall caisson mounted on a rubble mound foundation when waves are obliquely incident to the breakwater at an arbitrary angle.

TL;DR: In this article, the kinematics and dynamics of oscillatory flow in porous media are experimentally studied in an idealized porous structure and the concept of seepage velocity, extensively used in literature for the study of porous media, is analyzed.

TL;DR: In this article, an analytical expression for the vertical distribution of the correlation between the horizontal (ũ) and vertical (w) wave velocity components is presented, which appears explicitly in the time-averaged momentum balance equations.

TL;DR: In this paper, a series of tests demonstrate different aspects of wave chronology and its importance in the prediction of seabed and beach levels, using different reorderings of a wave sequence.

TL;DR: In this article, the authors studied the characteristics of pressures associated with plunging wave impacts on a vertical cylinder and provided a useful reference for future numerical and theoretical modelling of extreme wave loads on surface-piercing vertical cylinders.

TL;DR: In this paper, field measurements of cross-shore currents 0.25 m from the bed were made on two natural beaches under a range of incident wave conditions, and the results indicated the presence of a relatively strong, offshore-directed mean current, both within and seaward of the surf zone.

TL;DR: In this article, the effect of random waves on the bottom friction is studied by assuming that the wave motion is a stationary Gaussian narrow-band random process and the approach is also based on simple explicit friction coefficient formulas for sinusoidal waves.

TL;DR: In this paper, an oscillatory flow is obtained in a closed duct by the oscillations of two rigidly connected pistons located at the ends of the duct, which can be continuously varied.

TL;DR: In this article, the authors extended the concepts of unidirectional sheet flow to sinusoidal oscillatory motion and obtained relationships for friction factor and for the transition from bedforms to sheet flow.

TL;DR: In this paper, measurements, under laboratory conditions, of bottom velocities, wave heights, and breaking characteristics over an actively eroding consolidated cohesive sediment shore are reported, showing that erosion is enhanced under breaking conditions, and plunging breakers are markedly more erosive than spilling breakers.

TL;DR: In this paper, a maximum likelihood method is proposed to fit these simultaneous distributions to the triple annual maximum series, and an application of the method to the historical record at the Farallon Is. off San Francisco adopts several of the more common extreme value distributions.

TL;DR: In this article, a subgrid moveable-bed bottom friction model is developed for use in large-scale wind wave models, which defines a representative bottom roughness based on the local application of a discontinuous roughness model and a statistical description of depth, sediment and wave parameters for a finite area within the model.

TL;DR: In this paper, experiments were conducted in an oscillatory water tunnel to investigate what effects temporal inertia has on the resistance of a granular medium and the influence of properties of the medium (grain size and porosity) were tested by using spheres with two different diameters and packing each size sphere in different geometric arrangements.

TL;DR: In this article, a physical model test was carried out aiming to provide information on armor stone movements in a berm breakwaters, and the following items were examined: displacement threshold, frequency and length of stone displacements.

TL;DR: In this article, an advection/diffusion model is applied to this phenomenon, providing for cross-shore gradients in vertical eddy diffusivity within and beyond the surf zone which result in differential entrainment and settlement near the break point.

TL;DR: In this article, the combined threshold velocities indicate that under shorter (5 s) period waves, the oscillatory and steady flows are independent of each other, but interact to a greater extent as the wave period increases.

TL;DR: In this article, a nonlinearity parameter which is valid for both deep and shallow water waves is introduced, which may be regarded as a wave Froude number, and a modified form of the Ursell number is also discussed.

TL;DR: In this paper, a linear stability analysis of a flat sandy bottom subject to an oscillatory flow is presented, where the flow regime in the bottom boundary layer is assumed to be turbulent; hence previous works on the subject, which considered a laminar flow, are extended in a more relevant range of Reynolds number.

TL;DR: In this article, the authors proposed a very convenient formula to evaluate the friction coefficient induced by wave-current combined motion, which spans all flow regimes including the transitional regime and requires no iteration.

TL;DR: In this article, a time-dependent and a time independent wave equation is developed for waves propagating over porous rippled beds taking account of the effects of porous medium. But the results show that the reflected and transmitted waves become smaller than those in the case of impermeable rigid ripples due to energy dissipation in porous medium, and the Bragg scattering is examined in onedimensional case.

TL;DR: In this article, the dispersion relation and relationships for wave length and wave height can be obtained analytically, and the relevant approximate solution found by the method of the approximate dispersion relationship is applied for a practical calculation with satisfactory accuracy.