Hydrodynamics and morphodynamics in the swash zone: hydralab III large-scale experiments

Contestabile, Pasquale (2011) Hydrodynamics and morphodynamics in the swash zone: hydralab III large-scale experiments. [Tesi di dottorato] (Inedito)

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Abstract

The modelling of swash zone hydrodynamics and sediment transport and the resulting morphodynamics has been an area of very active research over the last decade. However, many details are still to be understood, whose knowledge will be greatly advanced by the collection of high quality data under controlled large-scale laboratory conditions. The advantage of using a large wave flume is that scale effects that affected previous laboratory experiments are minimized. In this work new large-scale laboratory data from two sets of experiments are presented. Physical model tests were performed in the large-scale wave flumes at the Grosser Wellen Kanal (GWK) in Hannover and at the Catalonia University of Technology (UPC) in Barcelona, within the Hydralab III program. The tests carried out at the GWK aimed at improving the knowledge of the hydrodynamic and morphodynamic behaviour of a beach containing a buried drainage system. Experiments were undertaken using a set of multiple drains, up to three working simultaneously, located within the beach and at variable distances from the shoreline. The experimental program was organized in series of tests with variable wave energy. While a positive effect was observed under low energy conditions, for medium and high energy conditions the benefit of having the drains operative was not always clear. In any case, it was evident that any positive effect of the drains on the beachface was confined by the position of the cone of depression in the aquifer’s surface. The tests carried out in the large wave flume at UPC had the intent to investigate swash zone under storm conditions. The main aim was to compare beach profile response for monochromatic waves, monochromatic waves plus free long waves, bichromatic waves and random waves. Both erosive and accretive conditions were considered. The experiments suggest that the inclusion of long wave and wave group sediment transport is important for improved nearshore morphological modelling of cross-shore beach profile evolution, and provide a very comprehensive and controlled series of tests for evaluating numerical models. It is suggested that the large change in the beach response between monochromatic conditions and wave group conditions is a result of the increased significant and maximum wave heights in the wave groups, as much as the presence of the forced and free long waves induced by the groupiness. The equilibrium state model concept can provide a heuristic explanation of the influence of the wave groups on the bulk beach profile response if their effective relative fall velocity is larger than that of monochromatic waves with the same incident energy flux.

Tipologia di documento:Tesi di dottorato
Altre informazioni:Dottorato di Ricerca in consorzio con - SECONDA UNIVERSITÀ DI NAPOLI - UNIVERSITÀ “PARTHENOPE” NAPOLI e in convenzione con - ISTITUTO PER L’AMBIENTE MARINO COSTIERO – C.N.R. - STAZIONE ZOOLOGICA “ANTON DOHRN”
Parole chiave:Swash Zone, Large Wave Flume, Beach Drainage System, Long Waves, Wave Groups, Beach Morphodynamics, Sediment Transport, Surf Beat
Settori scientifico-disciplinari MIUR:Area 08 Ingegneria civile e Architettura > ICAR/02 COSTRUZIONI IDRAULICHE E MARITTIME E IDROLOGIA
Coordinatori della Scuola di dottorato:
Coordinatore del Corso di dottoratoe-mail (se nota)
Incoronato, Albertoincorona@unina.it
Tutor della Scuola di dottorato:
Tutor del Corso di dottoratoe-mail (se nota)
Vicinanza, Diegodiegovic@unina.it
Stato del full text:Accessibile
Data:30 Novembre 2011
Numero di pagine:233
Istituzione:Università di Napoli Federico II
Dipartimento o Struttura:Scienze della Terra
Stato dell'Eprint:Inedito
Scuola di dottorato:Scienze della terra
Denominazione del dottorato:Scienze e ingegneria del mare
Ciclo di dottorato:24
Numero di sistema:8931
Depositato il:14 Dicembre 2011 12:56
Ultima modifica:03 Maggio 2012 11:31

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