Showing papers in "Coastal Engineering in 1991"

TL;DR: In this paper, a new form of the Boussinesq equations is introduced in order to improve their dispersion characteristics, and a numerical method for solving the new set of equations in two horizontal dimensions is presented.

TL;DR: In this article, the run-up of non-breaking and breaking solitary waves on plane impermeable beaches is investigated with a Lagrangian finite-element Boussinesq wave model.

TL;DR: In this article, the authors investigated water wave interactions with porous seabeds of granular material and found that the maximum wave damping was found when the dissipative resistance (velocity related) is equal to the non-dispensing resistance (acceleration related).

TL;DR: In this paper, an empirical expression for the width of the transition zone is developed from monochromatic wave data, and two techniques are proposed for the consideration of this phenomenon in the numerical modelling of surfzone hydrodynamics for random waves.

TL;DR: In this paper, the variability of incident wave groupiness in the field is examined both temporally, in unbroken waves at a fixed location, and spatially, in a cross-shore array through the surf zone.

TL;DR: In this paper, a model for the circulation current in the vertical plane in the surf zone, the so-called undertow, is formulated, which describes the time-averaged shear stresses caused by the wave breaking, which drives the current, and the resulting velocity distribution.

TL;DR: In this paper, a highly effective wave absorber containing a finite number of porous plates with various porous-effect parameters (G) is investigated and a formula for evaluating the reflection coefficient is derived.

TL;DR: In this paper, the authors analyzed local patterns of erosion and accretion that have resulted from the interruption of longshore sediment transport by jetties and groins as well as the major erosion of the promontories adjacent to the mouths of the Rosetta and Damietta branches of the Nile River, brought about by the cutoff of the supply of river sand by construction of the High Aswan Dam.

TL;DR: In this article, the authors compared the measured values of breaking wave height with earlier data and earlier expressions, and found that the present measured values are substantially lower, because the tests used irregular waves on a natural beach.

TL;DR: In this article, the authors describe experiments on uniform longshore currents in a wave basin with a pumped recirculation through openings in the wave guides, and show that minimal return flows in the offshore region of the basin are accompanied with long-shore currents which are virtually uniform alongshore.

TL;DR: The conceptual model approach appears to be promising, utilizing conceptual models which are made quantitative and validated with the aid of inductive ideas, such as those inferred from observed or through analogy expected behaviour to predict the longevity of shore nourishment.

TL;DR: In this article, the authors describe mathematical approaches for calculating the fate of beach fill under wave action, and an empirically based model is described and tested with a high-quality field data set of storm-induced beach erosion.

TL;DR: In this article, the authors analyzed the onshore-offshore transport of sediment on beaches by considering the time-averaged behaviour of a control volume bounded by the wave breaking zone and by the beach face.

TL;DR: In this article, a summary of carefully conducted laboratory experiments on the attenuation of simulated spectral waves propagating over an 18m-long bottom section covered by 10-cm-thick layers of 0.12-and 0.2-mm-diameter uniform quartz sands is presented.

TL;DR: In this article, the authors proposed a theoretical model to predict wave and current velocity profiles in the combined wave and currents motion near a fixed bed using the equation of motion and the eddy viscosity assumptions.

TL;DR: In this article, the authors discuss the environmental impact of beach and dune nourishment in terms of their environmental impact in borrow and fill areas, while also the landscaping requirements associated with replenishment activities.

TL;DR: In this paper, the effect of gradation of armour stones and the amount of rounded stones in the armour on dynamically stable breakwaters was assessed in a two-dimensional wave flume.

TL;DR: In this paper, the authors derived nonlinear shallow water equations of Airy and Boussinesq types to predict wave propagation over a porous sea bed and tested them against an integral equation method which solves the problem without any approximations for depth variations.

TL;DR: In this paper, the authors present a general discussion of the problems related to stress determination and describes the results and the analyses of model tests with 200 kg and 200 g load-cell instrumented Dolosse.

TL;DR: In this article, the reshaping of dynamically stable breakwaters was studied subject to variations in armour stone, (gradation and shape), wave characteristics and duration of wave attack from head on waves in a two dimensional wave flume.

TL;DR: In this paper, the dynamics of the vortex structures generated by flow separation at the ripple crest is investigated along with the mechanism through which sediments are lifted up from the bed and carried in suspension.

TL;DR: In this article, a numerical model is developed for the flow of water over a bottom topography that is characteristic of sandwaves found in the coastal and river estuary environment, and the Reynolds stresses are parameterised in terms of a gradient transfer law and an assumed partitioning of the turbulence energy between different components of the flow.

TL;DR: In this paper, the authors used a predictor which takes account of the textural properties of the native and borrow materials, the fill geometry and the incident wave climate to predict the behavior of beach fill.

TL;DR: In this article, a philosophy is given concerning the nourishment of sand at the offshore zone, the waterline, the dry beach, the dune front, and the top and the backside of a dune.

TL;DR: In this article, the set-up and results of a field experiment on sand-dike breach erosion are described, and it is found that the breaching process for the 2.2 m high sanddike is similar to that in Visser's (1988) laboratory experiments with a 0.6m high sand dike.

TL;DR: In this paper, a Bore-like surf beat with large wave height was discovered through field observations, and the wave height and wave velocity of the Bore like surf beat is lager than that of individual waves.

TL;DR: The Canadian Coastal Sediment Transport Programme (CCOAST) is designed to increase our knowledge of the dynamics of non-cohesive shorefaces through field measurement of sediment transport and the response of the bottom boundary under combined waves and currents as mentioned in this paper.

TL;DR: In this article, model tests were performed on breakwater sections armoured with Cubes and Tetrapods, and the number of moved units and number of impacts as a function of wave height, period and location on the slope.

TL;DR: In this paper, a computational scheme based on a single-phase fluid model has been constructed by formulating the vertical transport of mass and momentum within the sheet-flow layer, and the numerical results have shown the satisfactory agreements with the experimental results in velocity profile, sediment transport rate, and others.

TL;DR: In this paper, the authors defined a quantity r/pg(S-l)d, where r is boundary shear stress, p is fluid density, g is gravitational acceleration, S is the ratio of solids density to fluid density and d is particle diameter.