1,721,014 research outputs found
Interaction between waves and maritime structures
Full text linkUnderstanding the interaction between waves and maritime structures (IWMS) has been a primary concern for humans since ancient times, when they started sailing oceans and defending land from flooding and erosion.
The arguments of the papers gathered within this Special Issue can be categorized into:
Structural performance, concerning the stability/integrity of the structure (or any part thereof);
Functional performance, i.e., related to the capability of the structure to meet the scope for which it has been designed.
In turn, Item 2 may be subdivided into:
Hydraulic response, such as wave reflection, wave transmission, wave overtopping, etc.;
Morphodynamic response, which is the shoreline and beach response to a structure placement;
Floating body response, such as the oscillation of floating bodies or moored vessels.
This Special Issue includes 12 articles, four of which focus on structural performance and eight on functional response. The following section provides a brief summary of each of the contributions
Predicting wave transmission past Reef BallTM submerged breakwaters
No full textReef BallsTM are hemispherical shaped artificial units, made of neutral concrete and characterized by a particular surface textures to promote the growth of marine life. They can be arranged in different layouts to form submerged breakwaters, even of significant width. Although structures in Reef Balls have been employed for the protection of a number of top quality sites, no well-established design tool exists for the prediction of wave transmission behind them. In this article a set of equations is provided, based on the so-called "Conceptual Approach" originally developed for ordinary structures. The new expressions proved to fit properly more than 300 experimental data, coming from physical model tests conducted at two different American laboratories: Queen's University Coastal Engineering Research Laboratory (Canada) and the USACE Engineering Research and Development Center Coastal and Hydraulics Laboratory (USA). © Coastal Education & Research Foundation 2013
An overtopping formula for shallow water vertical seawalls by SWASH
Full text linkThere is now wide evidence that phase -resolving numerical models can capture the general physics of the overtopping process even under complex hydrodynamics. Based on this outcome, an extensive parametric study has been carried out with the model SWASH, to develop a design formula that uniformly predicts the overtopping rate at vertical seawalls for both breaking and non -breaking wave conditions. The use of the numerical model has allowed to vary the experimental conditions smoothly, avoiding the typical limitation of laboratory experiments. Furthermore, particular tests have been performed to assess whether, and up to which extent, the mean overtopping discharge is affected by the low frequency components of the incident wave spectrum. The formula relates the overtopping rate to a new water level statistic, which represents the average of the highest one-fourth wave displacements at the toe of the wall; it has initially been derived for planar beaches and then extended to the case of slope varying foreshores. A comparison with an array of 200 laboratory experiments confirms that the new parametrization can reduce the scatter of data compared to the EurOtop equation
On the evolution of beaches of finite length
No full textThis article provides closed form solutions of the Diffusion Equation (DE) for beaches of finite length bounded by outcrops; the method employed relies on the sum of two Sturm-Liouville Boundary Value Problems, which allow accounting for the effects of wave angle. From the general solution, three situations of engineering interest were extrapolated and discussed in detail. The first corresponds to a stretch of coast “pinned” at the extremes; the second refers to an “insulated” beach bounded by groins of infinite length and the third corresponds to a groin compartment bypassed at one end. All those solutions were previously known in the field of thermodynamics, but they are here derived systematically from a general Boundary Value Problem (BVP). A detailed comparison with the software GENESIS is carried out to establish the limits of application with increasing wave angles. The effects of the presence of outcrops is studied comparing the solutions for finite beaches with those proposed in the literature under the hypothesis of infinite shoreline (open coast). It is shown that the new approach can be particularly useful in the case of beach nourishments placed asymmetrically to the cell centre. For application purposes, approximate solutions are given, based on curve fitting, to calculate the remaining value of sediments in a beach fill of rectangular shape
Beaches in a semi-insulated compartment: Engineering tools from the diffusion theory
Full text linkBeaches can serve as a valuable asset to any community, which can gain a massive source of income from them;
in fact, beach tourism is ever more frequently the essential target of countries, aimed at attracting foreign investment or exchange. In this frame, prediction of coastal evolution at large scales is very important for coastal
management and first conceptual design. Management strategies, almost at the early stages of the projects, may
likely involve numerical simulations, but they can be extremely laborious, computing demanding and intensely
time-consuming especially when involving either wider coastal domain or longer time scales that basically encompasses the majority of coastal projects by now. Analytical solutions of the Diffusion Shoreline Equation (DSE)
can be a valid alternative. In these frames, given the surprisingly good predictive capabilities, they can isolate
essential features of the processes, making them more readily comprehended, and can avoid cumulative errors
associated with the accuracy of computational time-stepping models. Nevertheless, the rather complex mathematical form makes their use extremely challenging and confines them in the realm of high mathematics.
Ciccaglione et al. (2023) provided analytical solutions of the DSE for finite beaches bounded by outcrops of
whatever length (bypassing or non-bypassing groin compartments). Differently from the other studies, the authors checked the applicability range of the solutions through the comparison with reliable numerical models;
furthermore, using curve fitting analysis simple design tools were suggested to aid engineers in the practical
applications. In this paper, a deep focus is given on the case of a bypassing groin compartment, and easy-to-use
formulae are given to assess the lifetime of beach fill projects. A simple semi-theoretical solution is also given for
the case of a compartment bounded by a very short groin, by introducing a “convective term” modelled via a
Heavy-side function, H(x). The practical usefulness of this solution is proved through an application to the
evolution of a real beach along Italy’s Adriatic coast
Applicability of SWASH model for wave transformation and wave overtopping on vertical seawall
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Verification and re-calibration of an engineering method for predicting wave set up behind submerged breakwaters
No full textScogliere a cresta bassa e sommerse in presenza di onde frangenti: indagine sperimentale su modello in larga scala
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