1,720,988 research outputs found
An efficient method to identify cross-sea states from wave measurements
No full textThis paper is aimed at describing a simple and efficient method to identify cross-sea states from directional wave measurements. The method is based on a new parameter named "Cross-Sea Index" (CSI), which is defined as the difference between two distinct definitions of the overall mean wave direction: the classic one introduced by Longuet-Higgins and the more recent one suggested by De Girolamo. In the following, the theoretical basis of the method is firstly outlined. The influence of the directional spectrum characteristics on the Cross-Sea Index is then discussed. Afterwards, the results of two Monte Carlo simulations are shown. These simulations were aimed at testing the new method and at comparing its outcomes with those of three other existing criteria. Finally, the new method is applied to the directional wave measurements, which were recorded by the Italian Sea Wave monitoring Network (SWaN) during the storm on 26th December 1993. All the achieved results clearly show the efficiency of the herein-proposed method. (C) 2004 Elsevier B.V. All rights reserved
Three-dimensional experiments on landslide generated waves at a sloping coast
No full textThis paper describes new three dimensional experiments on water waves generated by landslides. The landslide is reproduced by a rigid elliptical body, sliding along an inclined plane (slope of 1/3, 1 vertical, 3 horizontal). The generated water waves are free to propagate both offshore and alongshore, since the plan dimensions of the used wave tank are of at least one order of magnitude larger than the width of the landslide, which can be considered to be a scale of the wave length. The experimental study has been carried out reproducing both subaerial and partially submerged landslides. The wave generation process is studied by means of video records of the near field flow and measurement of the landslide movement; the properties of the waves propagating along the coast are described on the basis of runup gauges. The waves observed during the experiments always present first a crest and then a trough; as the first wave propagates away from the generation area the crest tends to become smaller than the trough and the maximum runup along the coast is given by the second or by the third wave. An important feature is that the observed runup along the coast firstly grows with the distance from the generation area, it reaches a maximum value at about two times the width of the landslide. and then decreases. An estimate of the celerity at which the waves propagate along the coast is given on the basis of gauge measurements: it results that the crests propagate faster than the troughs, and the wave period increases. (C) 2009 Elsevier B.V. All rights reserved
SPH simulation of a floating body forced by regular waves
No full textThe dynamic analysis of a floating body response
under the wave forcing involves complex aspects related with
fluid-structure interaction. In this work a numerical approach
to solve such a problem is proposed by means of the SPH code.
Basic aspects regarding linear wave generation in a flume and
free-damped oscillations of a one degree of freedom (DOF)
floating box have been early investigated. Finally the fullycoupled
dynamic response of a floating breakwater forced by
regular waves has been analyzed and compared with
experimental measurements
Three-dimensional experiments on landslide generated waves at a sloping coast
No full textThis paper describes new three dimensional experiments on water waves generated by landslides. The landslide is reproduced by a rigid elliptical body, sliding along an inclined plane (slope of 1/3, 1 vertical, 3 horizontal). The generated water waves are free to propagate both offshore and alongshore, since the plan dimensions of the used wave tank are of at least one order of magnitude larger than the width of the landslide, which can be considered to be a scale of the wave length. The experimental study has been carried out reproducing both subaerial and partially submerged landslides. The wave generation process is studied by means of video records of the near field flow and measurement of the landslide movement; the properties of the waves propagating along the coast are described on the basis of runup gauges. The waves observed during the experiments always present first a crest and then a trough; as the first wave propagates away from the generation area the crest tends to become smaller than the trough and the maximum runup along the coast is given by the second or by the third wave. An important feature is that the observed runup along the coast firstly grows with the distance from the generation area, it reaches a maximum value at about two times the width of the landslide. and then decreases. An estimate of the celerity at which the waves propagate along the coast is given on the basis of gauge measurements: it results that the crests propagate faster than the troughs, and the wave period increases. (C) 2009 Elsevier B.V. All rights reserved
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