| Effect of Complex Wave Spectra on Sand Transport in Coastal Areas |
Period: September 2001 till March 2006
Status: Completed
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| Institute | Top | - KU Leuven; Afdeling Hydraulica, more, partner
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| Abstract | Coastal areas are highly dynamic and especially sensitive to short term natural hazards and anthropogenic interference. Therefore, anticipating their behavior when subjected to meteo-marine or other environmental conditions is crucial for a sustainable development and management. For this purpose, different numerical models for sediment transport are available; however, their performance is limited by the incomplete understanding of the governing processes and the very different time and space scales at which these processes take place.
Roughness is one of the major sources of error in sediment transport models in sandy nearshore areas, where the action of random waves is a dominant hydrodynamic feature. In this thesis, two types of roughness are investigated. First, the apparent roughness resulting from the interaction between waves and currents is studied. Yet, most of the work will be devoted to the investigation of ripple roughness and the effect of different wave spectra, including double peaked spectra, on ripple geometry and dimensions and on the resulting suspended sediment profiles.
The key tool is the use of full scale and reduced scale laboratory facilities. Measurements are investigated by combining existing knowledge and data with mathematical tools including engineering models for ripple prediction.
As a result, a better understanding of the reciprocal interaction between flow and roughness is achieved. In addition, a new comprehensive model for the interpretation of rippled beds is presented.
The high natural variability of the elements investigated in this thesis, in particular of the bed roughness, requires further research in order to quantify the resulting uncertainty and to determine if the accuracy of current sediment transport models can be significantly improved. |
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