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URI permanente para esta coleçãohttps://rihomolog.furg.br/handle/1/515

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2009 - 20103

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Assunto: search.filters.subject.Oscillating water column

Resultados da Pesquisa

Agora exibindo 1 - 3 de 3
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    Simulação numérica de um dispositivo de aproveitamento da energia das ondas do tipo coluna de água oscilante: comparação de dois códigos numéricos
    (2010) Conde, José Manuel Paixão; Teixeira, Paulo Roberto de Freitas; Didier, Eric Lionel
    Neste artigo apresentam-se os resultados da aplicação de dois códigos numéricos na simulação de um dispositivo de aproveitamento da energia das ondas do tipo coluna de água oscilante. Um dos códigos (FLUINCO) é baseado na técnica dos elementos finitos e o outro (FLUENT) na técnica dos volumes finitos. O objectivo do trabalho consiste na validação destes códigos para este tipo de escoamento, com o intuito de os aplicar de forma sistemática no projecto de sistemas de aproveitamento de energia das ondas. O caso simulado, que corresponde a um modelo simplificado testado experimentalmente, permitiu concluir da boa qualidade dos resultados obtidos, existindo uma boa correspondência entre os resultados experimentais e os obtidos pelos códigos numéricos.
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    Numerical analysis of regular waves over an onshore oscillating water column
    (2010) Davyt, Djavan Perez; Teixeira, Paulo Roberto de Freitas; Ramalhais, Rúben dos Santos; Didier, Eric Lionel
    The potential of wave energy along coastal areas is a particularly attractive option in regions of high latitude, such as the coasts of northern Europe, North America, New Zealand, Chile and Argentina where high densities of annual average wave energy are found (typically between 40 and 100 kW/m of wave front). Power estimated in the south of Brazil is 30kW/m, creating a possible alternative of source energy in the region. There are many types and designs of equipment to capture energy from waves under analysis, such as the oscillating water column type (OWC) which has been one of the first to be developed and installed at sea. Despite being one of the most analyzed wave energy converter devices, there are few case studies using numerical simulation. In this context, the numerical analysis of regular waves over an onshore OWC is the main objective of this paper. The numerical models FLUINCO and FLUENT® are used for achieving this goal. The FLUINCO model is based on RANS equations which are discretized using the two-step semi-implicit Taylor-Galerkin method. An arbitrary lagrangean eulerian formulation is used to enable the solution of problems involving free surface movements. The FLUENT® code (version 6.3.26) is based on the finite volume method to solve RANS equations. Volume of Fluid method (VOF) is used for modeling free surface flows. Time integration is achieved by a second order implicit scheme, momentum equations are discretized using MUSCL scheme and HRIC (High Resolution Interface Capturing) scheme is used for convective term of VOF transport equation. The case study consists of a 10.m deep channel with a 10 m wide chamber at its end. One meter high waves with different periods are simulated. Comparisons between FLUINCO and FLUENT results are presented. Free surface elevation inside the chamber; velocity distribution and streamlines; amplification factor (relation between wave height inside the chamber and incident wave height); phase angle (angular difference between the wave inside and outside the chamber); and sloshing parameter to quantify it inside the chamber are analised. Finally, a discussion of the potential and limitations of each numerical model as well as the behaviour of the onshore OWC device is presented.
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    Computational modeling of the air-flow in an oscillating water column system
    (2009) Gomes, Mateus das Neves; Olinto, Cláudio Rodrigues; Isoldi, Liércio André; Souza, Jeferson Avila; Rocha, Luiz Alberto de Oliveira
    Several alternatives for electric power production have been studied in the last decades. Because of the huge energetic resources stored in the oceans in the form of wave - about 2TW - value that is compared to the annual rate of electric power used in the earth, the conversion of the wave’s energy of the oceans in electric power comes up important as one of these alternatives. One of the ways to make that conversion is through the oscillating water column (OWC) system: the wave enters into the hydro-pneumatic chamber (resembling a cave with entry below the waterline) and the up-and-down movement of water column inside the chamber makes air flow to and from the atmosphere, driving an air turbine. The turbine is symmetric and is driven indifferently in which direction the air flows. This paper presents the computational modeling of the air flow in a oscillating water column chamber using two different methodologies: in one of them it is considered just the chamber, varying the velocity in its entrance according to the wave’s equation, considering just the air, and a new one considering the chamber put into a wave’s tank, so it takes in account the complete interaction between water and air into the chamber. In this method, to consider the water and air it is used the multiphase model volume of fluid (VOF). It was simulated the same geometric compound of an oscillating water column system with a vertically placed tower, in order to compare these two different numerical models. It is noted that the dimensions of the tested chamber are in laboratory scale and the proposed model was used to simulate a 2D case. It was used GAMBIT® software for geometry creation and mesh generation, while FLUENT® package was employed for solving the conservation equations and analysis of the results.