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dc.contributor.advisorBaquerizo Azofra, Asuncion-
dc.contributor.advisorLongo, Sandro-
dc.contributor.authorLira Loarca, Andrea-
dc.description.abstractThe modeling of the interactions of different forcing agents, such as wind and waves, and maritime structures is a challenging problem with significant applications in coastal engineering leading to a usual implementation of complex numerical models. However, at the predesign stages of a project, there is need for fast, efficient and accurate analytical models that allow the search of the optimal configurations according to different design criteria. Furthermore, the studies regarding structural optimization, analytical and experimental, often do not consider the effect of wind forcing on the incident and reflected swell wave trains and the interaction with local wind-driven waves due to the complexity of the nonlinear interactions taking place. Therefore, this thesis focuses on the study and modeling of wave-structure interactions of partially reflective maritime structures under swell and sea waves at different time scales, for which different methodologies are proposed and analyzed. Firstly, an analytical model for the oblique wave interaction of irregular waves with a maritime structure is proposed. The structure is delimited by a semi-submerged plate and a back wall enclosing a chamber. Then, a laboratory study of the same structure is carried out with experimental tests under paddlegenerated regular and irregular waves in combination with wind–sea waves for different wind speeds (wind tunnel) to account for the interaction of swell and sea waves. The analytical and experimental analyses focus on the effect of the geometry of the system characterized in terms of its relative submergence d/h and relative width B/L and the effects of wind-driven waves superimposed on swell on the overall behavior of the system. Finally, a methodology for the long-term simulation of extreme events is derived and used as forcing conditions impinging on the structure. Simulations using Monte Carlo techniques are performed to assess the uncertainty of the results. The analytical model provides a simple and efficient engineering tool to search for an optimal design (trade-off between performance and structural design) towards the goals of harbor tranquility in the far field region of the reflector, wave energy extraction in the inner chamber and structural safety analysis of the loads acting on the plate. It considers linear wave theory, taking into account the head loss due to the constriction of the flow. The results are compared to those obtained with computational fluid dynamics models, revealing that the proposed model is capable to efficiently describe the performance of these systems for weakly nonlinear incident waves.The performance of the system is studied by means of the reflection and capture coefficients and the structural component is dealt with by analyzing the maximum loads on the plate. The results showed that the behavior of the system varies with a periodicity at B cos q/L = 0.5. When dealing with irregular waves, the spectra at the seaward region and inside the chamber show a nodal and antinodal structure that varies with the distance to the reflector. This structure, as well as the phase lag between the free surface elevations at both sides of the plate, affects the total loads over the plate. The experimental tests involving the combination of paddle-generated regular and irregular waves with wind–sea waves (wind tunnel) provide an added value to the research as there are not many research facilities where it is possible to have controlled conditions of wind and paddle-generated waves. For the experiments involving incident regular wave with a wave period similar to the 1st natural period of the chamber, an amplification of wave energy in the seaward region is measured in the case of a relative submergence of d/h = 0.58, in agreement with the analytical model results. Wind–sea waves have a higher influence on the variation of the wave period of the waves seaward and leeward of the plate, and more so for the experiments with Tz0/T1 1.5. The influence of wind-driven waves on the overall performance of the system depends on the wave period of the swell wave. In order to analyze the behavior of the system in its useful life and under extreme conditions, a methodology for the long-term simulation of extreme events including the temporal evolution is developed. Extreme events are defined in combination of the threshold, the minimum storm duration and interarrival times by means of goodness-of-fit testing. The multivariate statistical characterization of the different maritime variables and their temporal dependence is studied by a combination of mixed probability distribution functions, vector autoregressive and copula models proving to be an efficient and accurate model to simulate long time series of extreme events. By means of Monte Carlo techniques, a large number of simulations were performed and applied to the analytical model to analyze the long-term performance of the structure and the uncertainty associated with the analysis.en_US
dc.publisherUniversità degli Studi di Parma. Dipartimento di Ingegneria civile e architetturaen_US
dc.publisherUniversità di Granadaen_US
dc.relation.ispartofseriesDottorato di Ricerca in Ingegneria Civileen_US
dc.rights© Andrea Lira Loarca, 2019en_US
dc.subjectcoastal engineeringen_US
dc.subjectwave transformationen_US
dc.titleExperimental and analytical study of the hydrodynamics of swell and sea waves with partially reflective structuresen_US
dc.typeDoctoral thesisen_US
Appears in Collections:Ingegneria civile, dell'Ambiente, del Territorio e Architettura. Tesi di dottorato

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