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Postgraduate Thesis: Numerical study of the hydrodynamic performance of a point-absorbing wave energy converter
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TitleNumerical study of the hydrodynamic performance of a point-absorbing wave energy converter
 
AuthorsDu, Qingjie.
杜青杰.
 
Issue Date2011
 
PublisherThe University of Hong Kong (Pokfulam, Hong Kong)
 
Abstract As fossil energy is depleting and global warming effect is worsening rapidly, developing renewable energies becomes the top priority in most countries. In recent years, wave energy has attracted more and more attention due to its high energy density and enormous global capacity. The goal of this study is to carry out a numerical study of the hydrodynamic performance of a point-absorbing wave energy converter. In this study, an accurate and efficient numerical wave fume was established first. Commercial software code FLUENT?, which is a state-of-the-art computer program package for modeling fluid flow and heat transfer, was used for the numerical simulation. Based on the Navier-Stokes equations for viscous, incompressible fluid and Volume of fluid (VOF) method, a numerical wave tank was developed. Dynamic meshing method was used to simulate the wavemaker, and Geo-Reconstruct scheme was used to capture and reconstruct the free surface. A wave-absorbing method employing porous medium model was proposed to act as the wave absorbing beach, which can absorb the wave energy efficiently. A series of regular waves were simulated using the proposed numerical method. Validation has been made by physical experiments. After developing the wave flume model, a cylinder, which represents the point-absorbing wave energy converter (WEC), was added into the wave flume. The hydrodynamic behavior of the WEC was studied. The numerical results were also compared with physical experiments. Based on the numerical simulation results, suggestions on optimizing the point-absorber are provided. In this study, eight wave cases, with different wave period and wave length were simulated. The results show that the numerical simulation can match well with the physical wave tank result. Both the wave height and wave period in different cases can match well between the numerical simulation and physical wave tank results. In the wave-cylinder simulation, the results also show a good match in the numerical study and physical study. This numerical model is very significant in ocean structure design. The cylinder tested in this study can be easily changed to a ship or an offshore-platform. Compared with the physical experiment, numerical simulation is more flexible. The simulation can be carried on a large time span and spatial scale. The geometry can be changed easily. Also the cost of numerical simulation is relatively cheap compared with the physical experiment.
 
AdvisorsLeung, YC
 
DegreeMaster of Philosophy
 
SubjectHydroelectric generators.
Ocean wave power.
 
Dept/ProgramMechanical Engineering
 
DOIhttp://dx.doi.org/10.5353/th_b4715284
 
DC FieldValue
dc.contributor.advisorLeung, YC
 
dc.contributor.authorDu, Qingjie.
 
dc.contributor.author杜青杰.
 
dc.date.hkucongregation2012
 
dc.date.issued2011
 
dc.description.abstract As fossil energy is depleting and global warming effect is worsening rapidly, developing renewable energies becomes the top priority in most countries. In recent years, wave energy has attracted more and more attention due to its high energy density and enormous global capacity. The goal of this study is to carry out a numerical study of the hydrodynamic performance of a point-absorbing wave energy converter. In this study, an accurate and efficient numerical wave fume was established first. Commercial software code FLUENT?, which is a state-of-the-art computer program package for modeling fluid flow and heat transfer, was used for the numerical simulation. Based on the Navier-Stokes equations for viscous, incompressible fluid and Volume of fluid (VOF) method, a numerical wave tank was developed. Dynamic meshing method was used to simulate the wavemaker, and Geo-Reconstruct scheme was used to capture and reconstruct the free surface. A wave-absorbing method employing porous medium model was proposed to act as the wave absorbing beach, which can absorb the wave energy efficiently. A series of regular waves were simulated using the proposed numerical method. Validation has been made by physical experiments. After developing the wave flume model, a cylinder, which represents the point-absorbing wave energy converter (WEC), was added into the wave flume. The hydrodynamic behavior of the WEC was studied. The numerical results were also compared with physical experiments. Based on the numerical simulation results, suggestions on optimizing the point-absorber are provided. In this study, eight wave cases, with different wave period and wave length were simulated. The results show that the numerical simulation can match well with the physical wave tank result. Both the wave height and wave period in different cases can match well between the numerical simulation and physical wave tank results. In the wave-cylinder simulation, the results also show a good match in the numerical study and physical study. This numerical model is very significant in ocean structure design. The cylinder tested in this study can be easily changed to a ship or an offshore-platform. Compared with the physical experiment, numerical simulation is more flexible. The simulation can be carried on a large time span and spatial scale. The geometry can be changed easily. Also the cost of numerical simulation is relatively cheap compared with the physical experiment.
 
dc.description.naturepublished_or_final_version
 
dc.description.thesisdisciplineMechanical Engineering
 
dc.description.thesislevelmaster's
 
dc.description.thesisnameMaster of Philosophy
 
dc.identifier.doihttp://dx.doi.org/10.5353/th_b4715284
 
dc.identifier.hkulb4715284
 
dc.languageeng
 
dc.publisherThe University of Hong Kong (Pokfulam, Hong Kong)
 
dc.relation.ispartofHKU Theses Online (HKUTO)
 
dc.rightsThe author retains all proprietary rights, (such as patent rights) and the right to use in future works.
 
dc.rightsCreative Commons: Attribution 3.0 Hong Kong License
 
dc.source.urihttp://hub.hku.hk/bib/B47152849
 
dc.subject.lcshHydroelectric generators.
 
dc.subject.lcshOcean wave power.
 
dc.titleNumerical study of the hydrodynamic performance of a point-absorbing wave energy converter
 
dc.typePG_Thesis
 
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 As fossil energy is depleting and global warming effect is worsening rapidly, developing renewable energies becomes the top priority in most countries. In recent years, wave energy has attracted more and more attention due to its high energy density and enormous global capacity. The goal of this study is to carry out a numerical study of the hydrodynamic performance of a point-absorbing wave energy converter.

In this study, an accurate and efficient numerical wave fume was established first. Commercial software code FLUENT?, which is a state-of-the-art computer program package for modeling fluid flow and heat transfer, was used for the numerical simulation. Based on the Navier-Stokes equations for viscous, incompressible fluid and Volume of fluid (VOF) method, a numerical wave tank was developed. Dynamic meshing method was used to simulate the wavemaker, and Geo-Reconstruct scheme was used to capture and reconstruct the free surface. A wave-absorbing method employing porous medium model was proposed to act as the wave absorbing beach, which can absorb the wave energy efficiently. A series of regular waves were simulated using the proposed numerical method. Validation has been made by physical experiments. 

After developing the wave flume model, a cylinder, which represents the point-absorbing wave energy converter (WEC), was added into the wave flume. The hydrodynamic behavior of the WEC was studied. The numerical results were also compared with physical experiments. Based on the numerical simulation results, suggestions on optimizing the point-absorber are provided. 

In this study, eight wave cases, with different wave period and wave length were simulated. The results show that the numerical simulation can match well with the physical wave tank result. Both the wave height and wave period in different cases can match well between the numerical simulation and physical wave tank results. In the wave-cylinder simulation, the results also show a good match in the numerical study and physical study. 

This numerical model is very significant in ocean structure design. The cylinder tested in this study can be easily changed to a ship or an offshore-platform. Compared with the physical experiment, numerical simulation is more flexible. The simulation can be carried on a large time span and spatial scale. The geometry can be changed easily. Also the cost of numerical simulation is relatively cheap compared with the physical experiment.</description.abstract>
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<subject.lcsh>Hydroelectric generators.</subject.lcsh>
<subject.lcsh>Ocean wave power.</subject.lcsh>
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