Este trabalho trata do desenvolvimento de um simulador simplificado para auxiliar no estudo da geração de ondas regulares em tanques de provas dotados de geradores segmentados, com foco em estudos sobre o Calibrador Hidrodinâmico, tanque de provas inaugurado na Universidade de São Paulo no ano de 2010. Este simulador simplificado utiliza fontes de onda pontuais para representar cada gerador e tem como sua principal vantagem, a economia de tempo em comparação a análises do problema de contorno potencial realizadas no domínio da freqüência utilizando, por exemplo, o método dos elementos de contorno. A verificação da validade da ferramenta desenvolvida foi feita através de comparações do caso bidimensional com ensaios realizados em um canal de ondas e, no caso tridimensional, com resultados fornecidos pelo programa Wamit, o qual resolve o problema de contorno potencial. Nestas comparações, o simulador demonstrou seu potencial, atingindo bons resultados. Uma vez validada, a ferramenta foi utilizada para analisar três diferentes configurações de operação do Calibrador Hidrodinâmico que podem vir a ser implementadas no futuro. As análises mostram que nenhuma das configurações é a melhor para todas as combinações de períodos e direções de propagação nas quais o tanque pode operar e podem servir como base para a definição de um procedimento de operação que vise garantir maior flexibilidade na utilização do tanque de provas mantendo a qualidade do campo de ondas gerado para os ensaios. / This work aims the development of a simplified simulator to assist the study about regular waves generation in test tanks equipped with segmented type wavemakers, focusing on the study about the Calibrador Hidrodinâmico (Hydrodynamics Calibrator), test tank inaugurated in 2010 at University of São Paulo. This simplified simulator uses punctual wave sources to represents each wavemaker end its main advantage is the computational time economy in comparison with analysis of the potential boundary problem made on frequency domain using, as example, the boundary elements method (BEM). To verify the developed tool validity, comparisons with bi-dimensional wave generation tests carried out on a flume were made. In three dimensional case, the comparisons were made with results provided by the program Wamit, which one solves the potential boundary problem. In all comparisons the results achieved were very good. Once proved the validity of simulator results, it was applied to analyze three different operational configurations of the Calibrador Hidrodinâmico, which can be implemented in future. The analysis showed that there is not a configuration with best results for all periods and propagation angles inside the tank operational limits and these results can be used to define a operation procedure that aims to ensure more flexibility on wavemakers operation to obtain the best possible wave field quality for all periods and propagation angles.

Este trabalho trata do desenvolvimento de um simulador simplificado para auxiliar no estudo da geração de ondas regulares em tanques de provas dotados de geradores segmentados, com foco em estudos sobre o Calibrador Hidrodinâmico, tanque de provas inaugurado na Universidade de São Paulo no ano de 2010. Este simulador simplificado utiliza fontes de onda pontuais para representar cada gerador e tem como sua principal vantagem, a economia de tempo em comparação a análises do problema de contorno potencial realizadas no domínio da freqüência utilizando, por exemplo, o método dos elementos de contorno. A verificação da validade da ferramenta desenvolvida foi feita através de comparações do caso bidimensional com ensaios realizados em um canal de ondas e, no caso tridimensional, com resultados fornecidos pelo programa Wamit, o qual resolve o problema de contorno potencial. Nestas comparações, o simulador demonstrou seu potencial, atingindo bons resultados. Uma vez validada, a ferramenta foi utilizada para analisar três diferentes configurações de operação do Calibrador Hidrodinâmico que podem vir a ser implementadas no futuro. As análises mostram que nenhuma das configurações é a melhor para todas as combinações de períodos e direções de propagação nas quais o tanque pode operar e podem servir como base para a definição de um procedimento de operação que vise garantir maior flexibilidade na utilização do tanque de provas mantendo a qualidade do campo de ondas gerado para os ensaios. / This work aims the development of a simplified simulator to assist the study about regular waves generation in test tanks equipped with segmented type wavemakers, focusing on the study about the Calibrador Hidrodinâmico (Hydrodynamics Calibrator), test tank inaugurated in 2010 at University of São Paulo. This simplified simulator uses punctual wave sources to represents each wavemaker end its main advantage is the computational time economy in comparison with analysis of the potential boundary problem made on frequency domain using, as example, the boundary elements method (BEM). To verify the developed tool validity, comparisons with bi-dimensional wave generation tests carried out on a flume were made. In three dimensional case, the comparisons were made with results provided by the program Wamit, which one solves the potential boundary problem. In all comparisons the results achieved were very good. Once proved the validity of simulator results, it was applied to analyze three different operational configurations of the Calibrador Hidrodinâmico, which can be implemented in future. The analysis showed that there is not a configuration with best results for all periods and propagation angles inside the tank operational limits and these results can be used to define a operation procedure that aims to ensure more flexibility on wavemakers operation to obtain the best possible wave field quality for all periods and propagation angles.

Coastal regions are vulnerable to various natural processes, ranging from normal waves to extreme events. Given the flourishing development and large population along coastlines, various measures have been taken to mitigate the water-induced damage. Nature-based coastal protection, especially vegetation, has attracted unprecedented studies over the past two decades. To enhance understanding of this subject, this dissertation evaluates the impact of patchy vegetation on wave and runup dynamics along coastlines. Selecting from a prototype in Dalehite Cove, Galveston Bay, TX, results from a Boussinesq model (COULWAVE) showed patchy vegetation reduced up to 75% mean shoreward current in the mound-channel wetland systems. These vegetation patches also reduced the primary circulation around mounds, with a power-form relation between circulation size and various parameters (i.e., bathymetry, incident wave and vegetated roughness). Substituting spectral waves for regular waves in the similar wetlands, more energy was transferred into the higher frequencies. The impact of patchy vegetation on wave energy was frequency- and space-dependent, with increased energy observed in specific harmonics and locations. Comparison with unvegetated horizontal bathymetry demonstrated that mound-channel bathymetry was the dominant factor in transferring and dissipating wave energy, while vegetation patches added a fair contribution. As for extreme events, such as tsunamis, laboratory experiments and numerical simulations were conducted to assess the effectiveness of patchy vegetation with various roughness levels, spacings and sizes. Overall, vegetation patches reduced the most destructive loads onshore by up to 80%. Within-patch roughness variation only caused uncertainty on the hydrodynamics around the seaward patches, while the mitigation of extreme loads was not undermined. A logarithmic relation was observed between the protected area from extreme loads and the vegetated coverage. These findings will fill the knowledge gap of hydrodynamics in the presence patchy vegetation, and improve the engineering practice of coastal protection using nature-based infrastructure. / Ph. D.

Hydro-synoptic analysis of floods on Berounka basin This thesis she aims to analyze the meteorological causes of floods, a database foundation flood situation and determine the potential effect of Šumava and Brdy flow of flood wave in Beroun. Overall, the relatively high impact of floods in Beroun have Úhlava (Šumava flow) and Klabava (Brdy flow). We can say that closer ties to the Šumava streams. Undoubtedly contributes to the shape of the basin after Serrated profile Plzen - Bílá Hora. Analysis of the meteorological causes of observed recurrent selected weather situations, but the most extreme floods (1978.1981, 2002) were caused by both type C. A detailed examination of the flood flows in the basin was prepared Berounka bank flood episodes. Keywords: Flood, the flood wave, basin Berounka, causal situation, hydro-synoptic analysis.

Fluid-structure interaction (FSI) is an interesting and challenging interdisciplinary area comprised of fields such as engineering- fluids/structures/solids, computational science, and mathematics. FSI has several practical engineering applications such as the design of coastal infrastructure (such as bridges, levees) subjected to harsh environments from natural forces such as tsunamis, storm surges, etc. Development of accurate input conditions to more detailed and complex models involving flexible structures in a fluid domain is an important requirement for the solution of such problems. FSI researchers often employ methods that use results from physical wave basin experiments to assess the wave forces on structures. These experiments, while closer to the physical phenomena, often tend to be time-consuming and expensive. Experiments are also not easily accessible for conducting parametric studies. Alternatively, numerical models when developed with similar capabilities will complement the experiments very well because of the lower costs and the ability to study phenomena that are not feasible in the laboratory. This dissertation is aimed at contributing to the solution of a significant component of the FSI problem with respect to engineering applications, covering accurate input to detailed models and a numerical wave basin to complement large-scale laboratory experiments. To this end, this work contains a description of a three-dimensional numerical wave tank (3D-NWT), its enhancements including the piston wavemaker for generation of waves such as solitary, periodic, and focused waves, and validation using large-scale experiments in the 3D wave basin at Oregon State University. Performing simulations involving fluid dynamics is computational-intensive and the complexity is magnified by the presence of the flexible structure(s) in the fluid domain. The models are also required to take care of large-scale domains such as a wave basin in order to be applicable to practical problems. Therefore, undertaking these efforts requires access to high-performance computing (HPC) platforms and development of parallel codes. With these objectives in mind, parallelization of the 3D-NWT is carried out and discussed in this dissertation. / Graduation date: 2011

This thesis describes experiments that were carried out using focused wave groups in the UK Coastal Research Facility (UKCRF). Considerable effort was put into calibrating the UKCRF to determine the relationship between the input signals sent to the paddles and the waves generated in the facility. Focused wave groups of various sizes and phases, based on NewWave theory were generated, and measurements were made of the resulting surface elevation data, water particle kinematics, wave runup and overtopping volumes. NewWave theory models the profile of extreme waves in a Gaussian (random) sea. The thesis describes the first time this model has been applied in the context of coastal wave transformation. A method for the separation of the underlying harmonic structure of a focused wave group is described and results presented. This technique has been used in relatively deep water but is shown to work successfully in the coastal zone until wave overturning. A method has been devised to provide a theoretical Stokes-like expansion of the free and bound waves to model the surface elevation and water particle kinematics of the focused wave groups. Satisfactory agreement is achieved between the theoretical predictions of UKCRF measurements. Suggestions are made for an improved model. The underlying harmonic structure of the focused wave groups is presented as stacked time histories that give insight into the wave transformation process from deep to shallow water. Particular attention is paid to the low frequency wave generated as the wave group interacts with the beach. This is compared to the low frequency wave that is generated by a solitary wave in the UKCRF. Runup and overtopping measurements are in reasonable agreement with predictions based on certain empirical formulae, but not others. These comparisons are useful in identifying those formulae able to predict runup and overtopping of extreme waves in the coastal zone.