OWC WEC integrated within a breakwater versus isolated: Experimental and numerical theoretical study

Howe, Damon; Nader, Jean-Roch

doi:10.1016/j.ijome.2017.07.008

Cited by 63 publications

(21 citation statements)

References 26 publications

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“…As far as investigations concerning the behavior of WECs integrated at a breakwater, theoretical hydrodynamic studies of an oscillating water column device (OWC) placed at the tip of a breakwater and along a straight coast were developed in [19,20]. Moreover, numerical analysis and experimental investigation into OWCs integrated at a flat breakwater have been presented in [21] whereas, in [22,23] a feasibility study of an OWC device integrated into a port in the Mediterranean Sea was presented. In [24,25] multiple OWCs structures integrated into floating breakwaters were investigated.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Evaluation of the Hydrodynamic Characteristics of Arrays of Vertical Axisymmetric Floaters of Arbitrary Shape in front of a Vertical Breakwater

Konispoliatis

Mavrakos

Katsaounis

2020

JMSE

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The present paper deals with the analytical evaluation of the hydrodynamic characteristics of an array of vertical axisymmetric bodies of arbitrary shape, placed in front of a reflecting vertical breakwater, which can be conceived as floaters for wave power absorption. At the first part of the paper, the hydrodynamic interactions between the floaters and the adjacent breakwater are exactly taken into account using the method of images, whereas, the interaction phenomena between the floaters of the array are estimated using the multiple scattering approach. For the solution of the problem, the flow field around each floater of the array is subdivided into ring-shaped fluid regions, in each of which axisymmetric eigenfunction expansions for the velocity potential are made. In the second part of the paper, extensive theoretical results are presented concerning the exciting wave forces and the hydrodynamic coefficients for various arrays’ arrangements of axisymmetric floaters. The aim of the study is to show parametrically the effect that the vertical breakwater has on the hydrodynamic characteristics of each particular floater.

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Section: Introductionmentioning

confidence: 99%

Theoretical Evaluation of the Hydrodynamic Characteristics of Arrays of Vertical Axisymmetric Floaters of Arbitrary Shape in front of a Vertical Breakwater

Konispoliatis

Mavrakos

Katsaounis

2020

JMSE

View full text Add to dashboard Cite

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“…(2016), Falcão, Henriques & Gato (2016), López et al. (2016), He, Leng & Zhao (2017) and Howe & Nader (2017). However, most of these studies are focused on 2-D problems, and therefore miss fundamental dynamics related to direction changes in wave diffraction and radiation from complex-shaped structures.…”

Section: Introductionmentioning

confidence: 99%

“…the chamber wall, the larger and broader the main peaks of the frequency response of wave power capture width. Numerical and physical studies on a coast/breakwaterintegrated OWC can be found in Morris-Thomas, Irvin & Thiagarajan (2007), He, Huang & Law (2012), Zhang, Zou & Greaves (2012), , Elhanafi et al (2016), , López et al (2016), He, Leng & Zhao (2017) and Howe & Nader (2017). However, most of these studies are focused on 2-D problems, and therefore miss fundamental dynamics related to direction changes in wave diffraction and radiation from complex-shaped structures.…”

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confidence: 99%

Wave power extraction from multiple oscillating water columns along a straight coast

et al. 2019

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The integration of oscillating water column (OWC) wave energy converters into a coastal structure (breakwater, jetty, pier, etc.) or, more generally, their installation along the coast is an effective way to increase the accessibility of wave power exploitation. In this paper, a theoretical model is developed based on the linear potential flow theory and eigenfunction matching method to evaluate the hydrodynamic performance of an array of OWCs installed along a vertical straight coast. The chamber of each OWC consists of a hollow vertical circular cylinder, which is half embedded in the wall. The OWC chambers in the theoretical model may have different sizes, i.e. different values of the radius, wall thickness and submergence. At the top of each chamber, a Wells turbine is installed to extract power. The effects of the Wells turbine together with the air compressibility are taken into account as a linear power take-off system. The hydrodynamic and wave power extraction performance of the multiple coast-integrated OWCs is compared with that of a single offshore/coast-integrated OWC and of multiple offshore OWCs. More specifically, we analyse the role of the incident wave direction, chamber size (i.e. radius, wall thickness and submergence), spacing between OWCs and number of OWCs by means of the present theoretical model. It is shown that wave power extraction from the coast-integrated OWCs for a certain range of wave conditions can be significantly enhanced due to both the constructive array effect and the constructive coast effect.

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“…The step adds a new resonant mechanism that takes place when the water volume above the step acts similarly to a rigid piston with its natural frequency of oscillation being close to the frequency of the incident wave. There exist also L-shaped OWC geometries in which a duct oriented in the direction of wave propagation is used to increase the resonant frequency of the system [10,11]. This concept was also used in the OWC module of the hybrid wave energy converter proposed in [12] that merges an OWC and an overtopping device.…”

Section: Introductionmentioning

confidence: 99%

Design Selection and Geometry in OWC Wave Energy Converters for Performance

et al. 2021

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Although oscillating water column (OWC) wave energy converters are arguably one of the most studied technologies, it is not clear which chamber geometry, among all of the available alternatives, would provide the best performance at a site of interest. In this work, a numerical model based on the Navier-Stokes equations for two compressible fluids, using a volume-of-fluid interface-capturing approach, is implemented to determine the best performing OWC geometry in a case study off the Port of Vigo (NW Spain). Four general shapes of OWC are analyzed: classic, stepped-bottom, U-shaped and L-shaped, and geometrical variants are investigated. In total, 18 chamber geometries are studied, considering the same turbine geometry in all of them. It was found that the U-shaped and L-shaped designs are the most easily tuned to resonate at a period of interest. Of these two, the L-shaped performs better. The best performance is achieved for an L-shaped OWC design with a shallow entrance, a high horizontal chamber duct and a wide vertical duct, for which a maximum capture-width ratio of 71.6% was achieved.

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OWC WEC integrated within a breakwater versus isolated: Experimental and numerical theoretical study

Cited by 63 publications

References 26 publications

Theoretical Evaluation of the Hydrodynamic Characteristics of Arrays of Vertical Axisymmetric Floaters of Arbitrary Shape in front of a Vertical Breakwater

Theoretical Evaluation of the Hydrodynamic Characteristics of Arrays of Vertical Axisymmetric Floaters of Arbitrary Shape in front of a Vertical Breakwater

Wave power extraction from multiple oscillating water columns along a straight coast

Design Selection and Geometry in OWC Wave Energy Converters for Performance

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