<p> Numerical simulations of waterjet inlets have been conducted in order to understand inlet performance during ship turning maneuvers. During turning maneuvers waterjet systems may experience low efficiency, cavitation, vibration, and noise. This study found that during turns less energy arrived at the waterjet pump relative to operating straight ahead, and that the flow field at the entrance of the waterjet pump exhibited a region of both low pressure and low axial velocity. The primary reason for the change in pump inflow uniformity is due to a streamwise vortex. In oblique inflow the hull boundary layer separates when entering the inlet and wraps up forming the streamwise vortex. These changes in pump inflow during turning maneuvers will result in increased unsteady loading of the pump rotor and early onset of pump rotor cavitation.</p><p> Simulations covered drift angles from 0&deg; to 30&deg;, pump velocities relative to free stream speed of 0.6 to 1.0 for inlet geometries with ramp angles of 25&deg; and 30&deg; with inlet-hull fairing radii relative to pump diameter of 0.1 to 0.2. The following observations were made: 1) the onset of the streamwise vortex occurred between drift angles of 5&deg; and 10&deg;; 2) increasing drift angle increased the strength of the streamwise vortex and lowered the energy of the flow entering the pump; 3) increasing the flow rate through the waterjet system increased the strength of the streamwise vortex; 4) increasing ramp angle tended to increase the strength of the streamwise vortex; and 5) increasing the fillet radius decreases the strength of the streamwise vortex.</p><p> Simulations of steady ahead operation of the waterjet propelled <i> R.V. Athena</i> were also conducted for Froude numbers of 0.34 to 0.84. From these simulations it was found that the pump inflow can be effectively approximated at a new ship speed from a known ship speed by scaling only the mean component of the axial velocity by the relative change in waterjet flow rate. Additionally, waterjet pump operating point and rotor blade inflow angles were found to independent of ship speed.</p>

Este projeto trata do estudo para implementação de um sistema de absorção/geração de ondas no Tanque de Provas Didático I do Departamento de Engenharia Naval e Oceânica da Universidade de São Paulo (PNV-EPUSP). As instalações já existentes incluem o tanque de provas, sensores de ondas resistivos e batedor de ondas do tipo cunha. Para a parte física do absorvedor, o sistema do servomotor foi disponibilizado pela MOOG do Brasil Controles Ltda. Dado que as propriedades desses equipamentos foram pré-definidas, os demais componentes foram escolhidos e projetados de acordo com esses parâmetros, levando-se em conta a compatibilidade com as características das instalações e a factibilidade de se adaptar e modificar os componentes para a realização de futuros ensaios com diferentes tipos de ondas. Tais componentes foram construídos com o suporte financeiro da Agência Nacional do Petróleo (ANP). O dimensionamento da placa basculante e a geometria do suporte do pistão são apresentados, bem como as caracterizações de cada item das instalações já existentes e do novo batedor de ondas destinado à absorção. Um algoritmo preliminar de controle é proposto e testado. Como houve a impossibilidade de se encaminhar o teste empírico do controlador no tanque do PNV, este foi executado na Yokohama National University (YNU, Japão). Os resultados numéricos mostram um bom desempenho do algoritmo, porém na implementação deste em equipamento físico, a análise dos testes mostrou que algumas melhorias devem ser realizadas para utilizações futuras. / This project presents the study for implementation of an absorbing/generating system in the Didactic Wave Tank I of the Department of Naval Architecture and Ocean Engineering of the Escola Politécnica of University of São Paulo (PNVEPUSP). The available facilities at the wave tank were resistance type sensors and a plunger-type wave maker. As the absorber\'s hardware, a servomotor system was applied, which was lent by MOOG do Brasil Controles Ltda., and the further components were designed and constructed with the financial support of the National Petroleum Agency (ANP). Since that equipment\'s properties were predefined, the constructed components\' geometry was decided concerning to the compatibility with the mentioned facilities. Also some attention was addressed to the requirement of being easily adaptive to modifications for later different kinds of wave experiments. The design steps of the new actuator and the description of the piston\'s support are shown, as well as the characterization of each item of the available facilities and new wave maker designated to be the absorber. A preliminary control algorithm is also proposed and tested. Since there was an impossibility of carrying out the controller\'s empirical tests in the tank of PNV, they took place in the Yokohama National University (YNU, Japan). The numerical results showed a good performance of the algorithm, however in the empirical tests\' analysis, some improvements were found necessary for future implementations.

Este projeto trata do estudo para implementação de um sistema de absorção/geração de ondas no Tanque de Provas Didático I do Departamento de Engenharia Naval e Oceânica da Universidade de São Paulo (PNV-EPUSP). As instalações já existentes incluem o tanque de provas, sensores de ondas resistivos e batedor de ondas do tipo cunha. Para a parte física do absorvedor, o sistema do servomotor foi disponibilizado pela MOOG do Brasil Controles Ltda. Dado que as propriedades desses equipamentos foram pré-definidas, os demais componentes foram escolhidos e projetados de acordo com esses parâmetros, levando-se em conta a compatibilidade com as características das instalações e a factibilidade de se adaptar e modificar os componentes para a realização de futuros ensaios com diferentes tipos de ondas. Tais componentes foram construídos com o suporte financeiro da Agência Nacional do Petróleo (ANP). O dimensionamento da placa basculante e a geometria do suporte do pistão são apresentados, bem como as caracterizações de cada item das instalações já existentes e do novo batedor de ondas destinado à absorção. Um algoritmo preliminar de controle é proposto e testado. Como houve a impossibilidade de se encaminhar o teste empírico do controlador no tanque do PNV, este foi executado na Yokohama National University (YNU, Japão). Os resultados numéricos mostram um bom desempenho do algoritmo, porém na implementação deste em equipamento físico, a análise dos testes mostrou que algumas melhorias devem ser realizadas para utilizações futuras. / This project presents the study for implementation of an absorbing/generating system in the Didactic Wave Tank I of the Department of Naval Architecture and Ocean Engineering of the Escola Politécnica of University of São Paulo (PNVEPUSP). The available facilities at the wave tank were resistance type sensors and a plunger-type wave maker. As the absorber\'s hardware, a servomotor system was applied, which was lent by MOOG do Brasil Controles Ltda., and the further components were designed and constructed with the financial support of the National Petroleum Agency (ANP). Since that equipment\'s properties were predefined, the constructed components\' geometry was decided concerning to the compatibility with the mentioned facilities. Also some attention was addressed to the requirement of being easily adaptive to modifications for later different kinds of wave experiments. The design steps of the new actuator and the description of the piston\'s support are shown, as well as the characterization of each item of the available facilities and new wave maker designated to be the absorber. A preliminary control algorithm is also proposed and tested. Since there was an impossibility of carrying out the controller\'s empirical tests in the tank of PNV, they took place in the Yokohama National University (YNU, Japan). The numerical results showed a good performance of the algorithm, however in the empirical tests\' analysis, some improvements were found necessary for future implementations.

Um projeto portuário adequado deve garantir a segurança dos navios atracados e a eficiência das atividades de carga e descarga. Para isso, é preciso boa combinação entre condições de abrigo (natural ou artificial), e sistemas de amarração e defensas. Em geral, os problemas mais sérios de atracação estão relacionados a efeitos de ressonância. Nesse contexto, as obras de abrigo são pouco eficazes porque elas não alteram significativamente os períodos dos fenômenos hidrodinâmicos, e a restrição dos movimentos dos navios atracados depende principalmente dos sistemas de linhas de amarração e de defensas. Analisar um sistema de amarrações e defensas implica estudar a dinâmica do sistema de um navio atracado (navio/amarração/defensas), as ações aplicadas (principalmente as ações ambientais), e as características dos componentes desse sistema. Propõe-se, dessa forma, um estudo para elaboração de modelos que ajudem na compreensão do comportamento dinâmico desse sistema e uma comparação dos resultados obtidos nos modelos com as exigências de documentos técnicos. Partido de análises de modelos estáticos simples até a introdução de não linearidades geométricas e de perda de contato, esta dissertação discute, inicialmente, métodos convencionais de obtenção de esforços de amarração. Em seguida, o sistema é avaliado por meio de modelos dinâmicos que permitem uma compreensão maior sobre o comportamento de um navio amarrado. / An appropriate harbour project should ensure the safety of moored ships and the efficiency of loading and unloading activities. For these reasons, a good combination of (natural or artificial) shelter conditions, mooring systems and fenders is necessary. In general, the most serious mooring problems are related to resonance effects. In this context, shelter structures are not very effective because they do not significantly alter the periods of hydrodynamic phenomena, and the restriction of the moored ships\' movements depends mainly on mooring lines and fenders. Analysing a system of mooring lines and fenders involves studying the dynamics of a moored ship\'s system (ship / mooring / fenders), the actions applied (mainly environmental actions) and the characteristics of the components of that mooring system. Therefore, this study carries out models that help in the understanding of the dynamic behaviour of this system; and makes a comparison of the results obtained in the models with the requirements of technical documents. From the analysis of simple static models to an introduction of geometric nonlinearities and contact loss, this dissertation discusses, initially, conventional methods of obtaining mooring efforts. Then, the system is evaluated by dynamic models that allow a greater understanding of the behaviour of a moored ship.