• Journal of Navigation and Port Research
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• v.37 no.6
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• pp.597-601
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• 2013

Recently, many studies about the wave power generation system for the marine structure as the hybrid form in linked with the original features have been made of. Of these, the wave power generation system using oscillating water column(OWC) has function to convert wave energy to electrical energy with original function of the break water structure. In this type of generation system, it is important to make the flow of sea water as much as possible without loss. Output characteristics of wave power generation system depending on entrance section were described in the paper. Also, flow quantity changing with entrance section, velocity of sea water and output of wells turbine were measured by simulating OWC wells turbine model in break water, one of the general marine structure. Finally, entrance section was suggested to enhance the energy conversion efficiency based on the results of simulation.

• Journal of the Korean Solar Energy Society
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• v.26 no.2
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• pp.1-7
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• 2006

A numerical investigation was performed to determine the effect of airfoil on the optimum flap height using NACA0015 Wells turbine. The five double flaps which have 0.5% difference were selected. A Navier-Stokes code, CFX-TASCflow, was used to calculate the flow field of the Wells turbine. The basic feature of the Wells turbine is that even though the cyclic airflow produces oscillating axial forces on the airfoil blades, the tangential force on the rotor is always in the same direction. Geometry used to define the three dimension numerical grid is based upon that of an experimental test rig. This paper tries to disign the double flap of Wells turbine with the numerical analysis.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.1
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• pp.182-190
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• 2001

The aerodynamics of the Wells turbine has been studied using 3-d, unstructured mesh flow solver for the Reynolds-averaged Navier-Stokes equations. The basic feature of the Wells turbine is that even though the cyclic airflow produces oscillating axial forces on the airfoil blades, the tangential force on the rotor is always in the same direction. Geometry used to define 3-D numerical grid is based upon that of an experimental test rig. The 3-D Wells turbine model, consisting of approximate 220,000 cells is tested of four axial flow rates. In the calculations the angle of attack has been varied between 10˚ and 30˚ of blades, Representative results from each case are presented graphically andy analysed. It is concluded that this technique holds much promise for future development of Wells turbines.

• 유체기계공업학회:학술대회논문집
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• 2000.12a
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• pp.325-333
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• 2000

The aerodynamics of the Wells turbine has been studied using a 3-dimensional, unstructured mesh flow solver for the Reynolds-averaged Navier-Stokes equations. The basic feature of the Wells turbine is that even though the cyclic airflow produces oscillating axial forces on the airfoil blades, the tangential force on the rotor is always in the same direction. Geometry used to define the 3-dimensional numerical grid is based upon that of an experimental test rig. The 3-dimensional Wells turbine model, consisting of approximate 220,000 cells is tested at four axial flow rates. In the calculations the angle of attack has been varied between $10^{\circ}$ and $30^{\circ}$ of blades. Representative results from each case are presented graphically and analyzed. It is concluded that this method holds much promise for future development of Wells turbines.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.616-621
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• 2001

A numerical investigation was performed to determine the effect of airfoil on the optimum flap height using NACA 0021 Wells turbine. The five double flaps which have 0.5% chord height difference were selected. A Navier-Stokes code, FLUENT, was used to calculate the flow field of the Wells turbine. The basic feature of the Wells turbine is that even though the cyclic airflow produces oscillating axial forces on the airfoil blades, the tangential force on the rotor is always in the same direction. Geometry used to define the 3-D numerical grid is based upon that of an experimental test rig. This paper tries to analyze the optimum double flap of Wells turbine with the numerical analysis.

• 유체기계공업학회:학술대회논문집
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• 2003.12a
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• pp.520-525
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• 2003

A numerical investigation was performed to determine the effect of airfoil on the optimum flap height using NACA0015 Wells turbine. The five double flaps which have 0.5% chord height difference were selected. A Wavier-Stokes code, CFX-TASCflow, was used to calculate the flow field of the Wells turbine. The basic feature of the Wells turbine is that even though the cyclic airflow produces oscillating axial forces on the airfoil blades, the tangential force on the rotor is always in the same direction. Geometry used to define the 3-D numerical grid is based upon that of an experimental test rig. This paper tries to analyze the optimum double flap of Wells turbine with the numerical analysis.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2001.05a
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• pp.69-74
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• 2001

The Wells turbine has hysteresis characteristics in a reciprocating flow. In this paper, in order to understand unsteady flow characteristics of the Wells turbine, a sinusoidal flow condition is simulated. The flow conditions and hysteresis characteristics, including blade thickness, are investigated over a period of time. The pressure distributions along the blade surface are investigated at mid-span to clarify the cause of the hysteresis. The result has shown that the hysteresis characteristics become more pronounced as blade thickness becomes larger. The occurrence of these characteristics depends on the varying behavior of wakes between an accelerating flow and a develerating flow.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.961-966
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• 2001

The Wells turbine is one of the simplest and most promising self-rectifying air turbines which are useful for the systems of alternative energy development in near future, and it is economically desirable from the point of view of the practical use, as well. To investigate the effect of blade sweep on the performance of the Wells turbine, computations of a fully 3-D Navier-Stokes are carried out under steady flow conditions of NACA0020 blade. It is known that the performance of the Wells turbine is considerably influenced by the blade sweep. An optimum blade sweep ratio(f=0.35) for the NACA0020 is found to be the most promising for the practical use, and this value is in good agreement with the previous experiments. It is also found that the overall turbine performance for the NACA0020 is better than that for the CA9.

• Journal of the Korean Solar Energy Society
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• v.23 no.3
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• pp.55-61
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• 2003

This paper represents the effect of rotor geometry on the performance of a small-scale Wells turbine for wave energy conversion. In this study, four kinds of blade profile were selected from previous studies with regard to the blade profile of the Wells turbine. The experimental investigations have been performed for two solidities by model testing under steady flow conditions, and then the effect of blade profile on the running and starting characteristics under sinusoidal flow conditions have been investigated by a numerical simulation using a quasi-steady analysis. In addition, the effect of sweep on the turbine characteristics has been investigated for the cases of CA9 and HSIM 15-262123-1576. As a result, a suitable choice of these design factors has been suggested.

• Journal of the Korean Solar Energy Society
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• v.23 no.2
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• pp.99-105
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• 2003

This paper presents the effect of rotor geometry on the performance of a small-scale Wells turbine for wave energy conversion. In this study, four kinds the Wells turbine of blade profile were selected from previous studies. The types of blade profile included in the papers are as follows: NACA0020 ; NACA0015; CA9; and HSIM 15-262123-1576. The experimental investigations have been performed for two solidities by testing model under steady flow conditions. The effect of blade profile on the running and starting characteristics under sinusoidal flow conditions have also been investigated by a numerical simulation based on a quasi-steady analysis. In addition, the effect of sweep on the turbine characteristics has been studied for the cases of CA9 and HSIM 15-262123-1576. Based on the evaluation, a suitable choice of these design factors has been suggested. As a result, it seems that a suitable choice of the sweep ratio of 0.35 for the blade profile of the Wells turbine.