The current study aims to perform a geometrical investigation of an onshore Oscillating Water Column (OWC) on a large scale. The Constructal Design method is employed, aiming to maximize its available power. The OWC is subjected to two constraints (areas of the chamber and ramp below the chamber); and three degrees of freedom: height/length ratio of the chamber (H1/L1), height/length ratio of the ramp (H2/L2), and submersion of the frontal wall of the chamber (H3). A laminar, unsteady, incompressible, and two-phase flow was adopted, solving conservation equations of mass, momentum, and transport of water-air volume fraction using Finite Volume Method (FVM) and Volume of Fluid (VOF) model. The global optimal geometry led to a twice maximized available power 37.3% higher than the best case without the seabed ramp below the chamber and seven times better than the worst case. Concerning the sensibility of geometry, results indicated that the chamber geometry, given by ratio H1/L1, over the available power (P) was strongly affected by the ramp ratio H2/L2. Moreover, the behavior of the effect of H2/L2 over the once maximized available power (Pm) and corresponding optimal shape of the chamber, (H1/L1)o, changed dramatically for two different magnitudes of H3 investigated.

This work presents a numerical study to evaluate the difference between the fluid dynamic behavior of an overtopping device subjected to the incidence of a realistic wave when compared to a regular one; being this regular wave representative of the considered realistic sea state. To do so, the FLUENT software was employed, which is a Computational Fluid Dynamics package based on the Finite Volume Method. The regular wave was generated through a User Defined Function (UDF) that imposes its velocities components as boundary conditions of prescribed velocity. On the other hand, for the realistic wave it was used a methodology to impose the realistic components velocities from transient discrete values, named Table Data (TD) in FLUENT software. For both cases the Volume of Fluid (VOF) multiphase model was applied in the treatment of the water-air interaction. The results showed that the amount of water accumulated in the reservoir for the realistic sea state was 2.46 higher than for the regular wave. This is a relevant finding, since several researches about Overtopping device efficiency were promoted considering only the incidence of regular wave.

Este trabalho busca avaliar geometricamente, através do Design Construtal, um caminho de alta condutividade a fim de melhor distribuir o campo de temperaturas diminuindo a maior temperatura observada em um domínio com geração de calor e de baixa condutividade. Para a análise numérica deste estudo, foi utilizado o software MATLAB junto com a ferramenta PDETOOL (Partial Differential Equation Toolbox). O caminho condutivo possui uma forma de seta, ou seja, composto por uma parte retangular com razão de medidas variáveis e uma parte triangular de área fixa. O problema passa a ter três restrições de área com seis variáveis, resultando em três graus de liberdade, H/L, H0/L0 e H1/L1, sendo que apenas H0/L0 varia. As simulações numéricas foram feitas para três diferentes condutividades, considerando quatro valores de fração de área preestabelecidos. Foi possível obter a geometria do caminho condutivo que melhor distribui o campo de temperaturas, resultando na minimização da temperatura máxima. Observouse nas três diferentes condutividades que, quanto maior a distribuição da área ocupada pelo material de alta condutividade em relação à área da placa, melhor distribuída será a temperatura, resultando na redução da temperatura máxima observada. Constatou-se também que a mais baixa condutividade térmica analisada, apresentou a menor temperatura máxima à medida que a razão do grau de liberdade foi aumentando. Já a maior condutividade térmica analisada apresentou menor temperatura máxima à medida que a razão do grau de liberdade foi diminuindo.

The present study aims to evaluate the difference in the fluid-dynamic behavior of an overtopping wave energy converter under the incidence of irregular waves based on a realistic sea state when compared to the incidence of regular waves, representative of this sea state. Thus, the sea data of three regions from the Rio Grande do Sul coast, Brazil, were considered. Fluent software was employed for the computational modeling, which is based on the finite volume method (FVM). The numerical generation of waves occurred through the imposition of the velocity boundary conditions using transient discrete values through the WaveMIMO methodology. The volume of fluid (VOF) multiphase model was applied to treat the water–air interaction. The results for the water amount accumulated in the device reservoir showed that the fluid-dynamic behavior of the overtopping converter has significant differences when comparing the two proposed approaches. Differences up to 240% were found for the water mass accumulated in the overtopping device reservoir, showing evidence that the results can be overestimated when the overtopping device is analyzed under the incidence of the representative regular waves. Furthermore, for all studied cases, it was possible to approximate the water volume accumulated over time in the overtopping reservoir through a first-degree polynomial function.