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Abstract(s)
O oceano é um tema de interesse e de descoberta infinito. O seu estudo é fundamental, não só no meio onde nos inserimos mas também para a população em geral. Este trabalho debruça-se sobre uma ínfima parte do oceano, que são as fontes hidrotermais. Estas, são descargas de água a alta temperatura que se desenvolvem a partir do fundo do oceano. São uma grande fonte de biodiversidade e interesse, no entanto são ainda um pouco desconhecidas.
Baseados em estudos anteriores, optámos por aprofundar o nosso estudo no comportamento da trajetória do raio sonoro no interior destas fontes. Numa primeira parte deste trabalho, fizemos uma revisão que nos ajudou a entender melhor, não só as fontes hidrotermais, como também o comportamento do som no oceano.
De seguida, introduzimos duas equações da velocidade do som já conhecidas, para avaliar o comportamento do raio sonoro no interior das fontes, tendo em conta as alterações nos parâmetros da água. Os parâmetros estudados no presente trabalho foram: a temperatura, a profundidade e a salinidade, sendo que parece poder afirmar-se, que aquele que apresenta maior influência é a temperatura. De acordo com os estudos iniciais, foram construídos alguns modelos com o objetivo de obtermos uma visão inicial dos resultados pretendidos.
Importa referir, que após a leitura aprofundada sobre esta matéria, baseada em investigações anteriores, considerámos a tomografia acústica, ou seja definimos que não só estudaríamos a trajetória do raio sonoro ao longo da fonte mas, também, os tempos efetuados pelo mesmo. Com isto, sugerimos a colocação de emissores e recetores ao redor da fonte, o que nos permitiu observar o comportamento das trajetórias. Isto porque são introduzidos parâmetros iniciais como por exemplo, a posição do emissor e o ângulo de emissão do mesmo.
Os resultados deste trabalho são efetuados através da ferramenta MATLAB e apresentados em gráficos que contêm os desenhos das trajetórias e os tempos calculados das mesmas.
The study of the ocean is a theme of infinite interest and discovery. Not only for navy officials but also for the population in general. This work focuses on a tiny part of the ocean, that which concerns the recently discovered hydrothermal vents. These are discharges of very hot water that escape through crevices from the bottom of the ocean. They are a great source of biodiversity and interest, but still largely unstudied as regards their morphology, composition, possible economic interest and so on. Having reviewed some previous recent studies, we choose to deepen our study on the behaviour of the sound ray trajectories through these vents. In a first part of this work, we did a review that helped us to understand better, the propagation of sound, with ray approximation, through pre-defined temperature field modelling simple deep water hydrothermal vent. Next, we introduce some known sound velocity equations in order to be able to evaluate the behaviour of the sound rays due to changes in the water parameters. Such as temperature, depth and salinity. The one that has greater influence in this case is the temperature. With these initial studies, some models were constructed so that we had an initial assessment of what one should observe in the field experiments. We also considered besides the trajectory of the sound ray through the vents, the times of their propagation between emitter and receiver properly placed around the source. The different trajectories and propagation times, vary as we choose different initial positions of the emitter and of the angle of emission of the ray relative to the vent, but always in a horizontal plane. The results of this work are obtained by solving a nonlinear ODE (ordinary differential equation) with MATLAB and are shown in various graphs containing drawings of the trajectories and their calculated times.
The study of the ocean is a theme of infinite interest and discovery. Not only for navy officials but also for the population in general. This work focuses on a tiny part of the ocean, that which concerns the recently discovered hydrothermal vents. These are discharges of very hot water that escape through crevices from the bottom of the ocean. They are a great source of biodiversity and interest, but still largely unstudied as regards their morphology, composition, possible economic interest and so on. Having reviewed some previous recent studies, we choose to deepen our study on the behaviour of the sound ray trajectories through these vents. In a first part of this work, we did a review that helped us to understand better, the propagation of sound, with ray approximation, through pre-defined temperature field modelling simple deep water hydrothermal vent. Next, we introduce some known sound velocity equations in order to be able to evaluate the behaviour of the sound rays due to changes in the water parameters. Such as temperature, depth and salinity. The one that has greater influence in this case is the temperature. With these initial studies, some models were constructed so that we had an initial assessment of what one should observe in the field experiments. We also considered besides the trajectory of the sound ray through the vents, the times of their propagation between emitter and receiver properly placed around the source. The different trajectories and propagation times, vary as we choose different initial positions of the emitter and of the angle of emission of the ray relative to the vent, but always in a horizontal plane. The results of this work are obtained by solving a nonlinear ODE (ordinary differential equation) with MATLAB and are shown in various graphs containing drawings of the trajectories and their calculated times.
Description
Keywords
Acústica Oceano Fonte Hidrotermal Refração Trajetória Acoustic Ocean Hydrothermal Vent Refraction Trajectory