Experimental and numerical investigations on the hydrodynamic performance of a floating–moored oscillating water column wave energy converter

Elhanafi, Ahmed; Macfarlane, Gregor; Fleming, Alan; Leong, ZQ

doi:10.1016/j.apenergy.2017.07.138

Cited by 110 publications

(26 citation statements)

References 39 publications

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“…Therefore, LCs in the same location, e.g., LC1 and LC3, have an in-phase and reflect the free surface variations. The variation of the water surface elevation and the air pressure inside the chamber represent the air exchange rate through the orifice so that the velocity of the water surface inside the chamber and the airflow rate at the PTO can be calculated, assuming air compressibility effect is negligible for small-model scales [14,25]. In fact, the air compressibility does not take place at the scale of the tested, as proved by [25], and the experimental measurements can be corrected in the later processing of data results, as proposed by [26].…”

Section: Owc Wec Motions In Six Degrees Of Freedommentioning

confidence: 99%

“…They conducted experiments at a very small-scale (1:120) using soft mooring lines, but they neither measured tensions in the lines, nor did they study extreme conditions. In a more recent study, both fixed and floating-moored OWC WECs were tested with a scale of 1/50 [14]. They measured several parameters by conducting a comprehensive experiment with tight mooring lines.…”

Section: Introductionmentioning

confidence: 99%

“…It is important to measure simultaneously: water surface variation in the chamber and at the vicinity of the model, tension loads originating from the mooring lines, air velocity in the air tube orifice, pressure variations in the model chamber, and all 6 DOF of the model motions. If the air in the OWC chamber behaves as an incompressible fluid (as it happens in case of specific testing conditions), measuring the air pressure and water level variations in the chamber is enough for determining the airflow velocity through the vent [14]. Meanwhile, different numerical models are established to simulate the dynamics of OWC WECs.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Efficiency and Survivability of a Floating Oscillating Water Column Wave Energy Converter Moored to the Seabed: An Overview of the EsflOWC MaRINET2 Database

Kisacik

Stratigaki

et al. 2020

Water

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Floating oscillating water column (OWC) type wave energy converters (WECs), compared to fixed OWC WECs that are installed near the coastline, can be more effective as they are subject to offshore waves before the occurrence of wave dissipation at a nearshore location. The performance of floating OWC WECs has been widely studied using both numerical and experimental methods. However, due to the complexity of fluid–structure interaction of floating OWC WECs, most of the available studies focus on 2D problems with WEC models of limited degrees-of-freedom (DOF) of motion, while 3D mooring effects and multiple-DOF OWC WECs have not been extensively investigated yet under 2D and 3D wave conditions. Therefore, in order to gain a deeper insight into these problems, the present study focuses on wave flume experiments to investigate the motion and mooring performance of a scaled floating OWC WEC model under 2D wave conditions. As a preparatory phase for the present MaRINET2 EsflOWC (efficiency and survivability of floating OWC) project completed at the end of 2017, experiments were also carried out in advance in the large wave flume of Ghent University. The following data were obtained during these experimental campaigns: multiple-DOF OWC WEC motions, mooring line tensions, free surface elevations throughout the wave flume, close to and inside the OWC WEC, change in the air pressure inside the OWC WEC chamber and velocity of the airflow through the vent on top of the model. The tested wave conditions mostly include nonlinear intermediate regular waves. The data obtained at the wave flume of Ghent University, together with the data from the EsflOWC tests at the wave flume of LABIMA, University of Florence, provide a database for numerical validation of research on floating OWC WECs and floating OWC WEC farms or arrays used by researchers worldwide.

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Section: Owc Wec Motions In Six Degrees Of Freedommentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Efficiency and Survivability of a Floating Oscillating Water Column Wave Energy Converter Moored to the Seabed: An Overview of the EsflOWC MaRINET2 Database

Kisacik

Stratigaki

et al. 2020

Water

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“…Luo et al [11] reports simulations of a heave-only floating OWC WEC connected to a spring type of mooring system in a numerical wave tank developed using the Fluent software [12]. Elhanafi et al [13] thoroughly described a fully 3D numerical investigation of the hydrodynamic behavior of a floating moored OWC WEC by means of the STAR-CCM+ software [14] and validated their results using experimental data. The mooring lines in the employed tests are simulated by four pretensioned springs and are connected vertically to loadcells, and the mooring survivability is investigated in Elhanafi et al [15].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of a Moored Floating Oscillating Water Column Wave-Energy Converter and of a Moored Cubic Box

Stratigaki

Troch

et al. 2019

Energies

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This paper describes experimental research on a floating moored Oscillating Water Column (OWC)-type Wave-Energy Converter (WEC) carried out in the wave flume of the Coastal Engineering Research Group of Ghent University. This research has been introduced to cover the existing data scarcity and knowledge gaps regarding response of moored floating OWC WECs. The obtained data will be available in the future for the validation of nonlinear numerical models. The experiment focuses on the assessment of the nonlinear motion and mooring-line response of a 1:25 floating moored OWC WEC model to regular waves. The OWC WEC model motion has 6 degrees of freedom and is limited by a symmetrical 4-point mooring system. The model is composed of a chamber with an orifice on top of it to simulate the power-take-off (PTO) system and the associated damping of the motion of the OWC WEC model. In the first place, the motion response in waves of the moored floating OWC WEC model is investigated and the water surface elevation in the OWC WEC chamber is measured. Secondly, two different mooring-line materials (iron chains and nylon ropes) are tested and the corresponding OWC WEC model motions and mooring-line tensions are measured. The performance of these two materials is similar in small-amplitude waves but different in large wave-amplitude conditions. Thirdly, the influence of different PTO conditions is investigated by varying the diameter of the top orifice of the OWC WEC model. The results show that the PTO damping does not affect the OWC WEC motion but has an impact on the water surface elevation inside the OWC chamber. In addition, an unbalanced mooring configuration is discussed. Finally, the obtained data for a moored cubic model in waves are presented, which is a benchmarking case for future validation purposes.

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“…A investigação da otimização geométrica de dispositivos conversores de energia das ondas do mar é um tema de pesquisa que permeia muitos trabalhos científicos dentre eles destacam-se alguns autores brasileiros como Gomes (2014) [6], Barbosa (2016) [7] e Martins (2016) [8]. Trabalhos internacionais também já foram realizados, dentre eles destacam-se Vyzikas et al (2017) [1], Rezanejad et al (2017) [5], Elhanafi et al (2017) [9] e Connell et al (2018) [10].…”

Section: Introductionunclassified

Investigação numérica da descontinuidade geométrica entre a entrada e a saída de um conversor de energia das ondas do mar do tipo coluna de água oscilante

et al. 2019

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A investigação realizada apresenta um estudo bidimensional de um dispositivo conversor de energia das ondas do mar do tipo Coluna de Água Oscilante (CAO) avaliado de forma numérica. Foram analisados três graus de liberdade H1/L (razão entre a altura e o comprimento da câmara CAO), H3 (profundidade de submersão do dispositivo CAO) e L/l (relação entre largura da câmara e da chaminé do dispositivo), no qual foi avaliado o efeito da variação geométrica no efeito de pistão, vazão mássica e pressão transiente para descontinuidade geométrica. A metodologia utilizada para avaliação numérica se fez através da utilização de um código comercial de dinâmica dos fluidos computacional, baseado no Método de Volumes Finitos (MVF). Como o trabalho apresenta interação entre dois fluidos imiscíveis (água e ar), utiliza-se o modelo multifásico Volume of Fluid (VOF). Os resultados obtidos mostram que à medida que L/l diminui (por consequência a descontinuidade geométrica tende a diminuir) os picos negativos de pressão deixam de existir e a distribuição de pressões tende a ficar simétrica, e isso ocorre sempre quando H1/L tende a aumentar.

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Experimental and numerical investigations on the hydrodynamic performance of a floating–moored oscillating water column wave energy converter

Cited by 110 publications

References 39 publications

Efficiency and Survivability of a Floating Oscillating Water Column Wave Energy Converter Moored to the Seabed: An Overview of the EsflOWC MaRINET2 Database

Efficiency and Survivability of a Floating Oscillating Water Column Wave Energy Converter Moored to the Seabed: An Overview of the EsflOWC MaRINET2 Database

Experimental Study of a Moored Floating Oscillating Water Column Wave-Energy Converter and of a Moored Cubic Box

Investigação numérica da descontinuidade geométrica entre a entrada e a saída de um conversor de energia das ondas do mar do tipo coluna de água oscilante

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