Publicação
Wave hydrodynamics in coastal stretches influenced by detached breakwaters
| Resumo: | Coastal zones are highly dynamic systems directly influenced by natural driving forces and human induced impacts. Understanding the fundamentals of the physical, chemical, biological and anthropogenic phenomena related to these natural environments is of vital importance for coastal human life and property protection. Due to the predicted sea level rise over the next century and the increase in frequency and severity of storms, beaches and coastal defence structures are at risk. The worsening of erosion, with the consequent reduction of shorelines has great impact in the environment, in tourism and economy of regions affected by this problem. In order to protect coastal areas, defence structures reveal an important role in shielding urban areas. Many different engineering solutions can be used to reduce or to control coastal erosion, such as: breakwaters, groins, environmental-friendly structures and beach nourishment. In this work the impact in hydrodynamics and sediment transport of a detached breakwater on the Portuguese Ofir beach was considered as a case study. The geometric parameters of a reference detached breakwater were obtained using UK Department of Environment Food and Rural Affairs methodology based on data of wave characteristics and bathymetry obtained from field measurements and from the Portuguese Hydrographic Institute monitoring stations. Ocean hydrodynamic data for a period between 1993 and 2007 obtained in the Leixões buoy were considered in the implementation of numerical models in order to understand the wave conditions in Ofir beach. The selected software for models construction were the COULWAVE (1D) for hydrodynamics (significant wave height and wave energy) and BOUSS-2D for 2DH hydrodynamics (significant wave height and water residual velocity). The input data needed depended on the characteristics of each one of those models. The combination of the parameters needed for the running of each model determined different simulation scenarios considering the situation of continuous and discontinuous detached breakwaters and the natural situation without detached breakwaters. In addition, a sensitivity analysis for comparing relative accuracy for significant wave height results between the two models was performed. |
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| Autores principais: | Vieira, Bárbara Filipa Vasquez |
| Assunto: | Coastal hydrodynamics Detached breakwater Mathematical modelling Hidrodinâmica Modelação matemática Quebramar destacado |
| Ano: | 2014 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | Coastal zones are highly dynamic systems directly influenced by natural driving forces and human induced impacts. Understanding the fundamentals of the physical, chemical, biological and anthropogenic phenomena related to these natural environments is of vital importance for coastal human life and property protection. Due to the predicted sea level rise over the next century and the increase in frequency and severity of storms, beaches and coastal defence structures are at risk. The worsening of erosion, with the consequent reduction of shorelines has great impact in the environment, in tourism and economy of regions affected by this problem. In order to protect coastal areas, defence structures reveal an important role in shielding urban areas. Many different engineering solutions can be used to reduce or to control coastal erosion, such as: breakwaters, groins, environmental-friendly structures and beach nourishment. In this work the impact in hydrodynamics and sediment transport of a detached breakwater on the Portuguese Ofir beach was considered as a case study. The geometric parameters of a reference detached breakwater were obtained using UK Department of Environment Food and Rural Affairs methodology based on data of wave characteristics and bathymetry obtained from field measurements and from the Portuguese Hydrographic Institute monitoring stations. Ocean hydrodynamic data for a period between 1993 and 2007 obtained in the Leixões buoy were considered in the implementation of numerical models in order to understand the wave conditions in Ofir beach. The selected software for models construction were the COULWAVE (1D) for hydrodynamics (significant wave height and wave energy) and BOUSS-2D for 2DH hydrodynamics (significant wave height and water residual velocity). The input data needed depended on the characteristics of each one of those models. The combination of the parameters needed for the running of each model determined different simulation scenarios considering the situation of continuous and discontinuous detached breakwaters and the natural situation without detached breakwaters. In addition, a sensitivity analysis for comparing relative accuracy for significant wave height results between the two models was performed. |
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