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\n  \n 2019\n \n \n (2)\n \n \n
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\n \n\n \n \n \n \n \n Lift-based wave energy converters – an analysis of their potential.\n \n \n \n\n\n \n Folley, M.; and Whittaker, T.\n\n\n \n\n\n\n In 13th European Wave and Tidal Energy Conference, 2019. \n \n\n\n\n
\n\n\n\n \n\n \n\n \n link\n  \n \n\n bibtex\n \n\n \n  \n \n abstract \n \n\n \n\n \n \n \n \n \n \n \n\n  \n \n \n\n\n\n
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@inproceedings{\n title = {Lift-based wave energy converters – an analysis of their potential},\n type = {inproceedings},\n year = {2019},\n city = {Naples, Italy},\n id = {98c591d9-0e3a-347b-b614-58e705929b1c},\n created = {2020-04-03T12:32:36.329Z},\n file_attached = {false},\n profile_id = {80f79df7-70c4-3a7b-8290-0309ce34e49b},\n group_id = {a8cd9ed8-fd6b-32bd-a7ad-27ef75b1faca},\n last_modified = {2020-04-03T12:32:36.329Z},\n read = {false},\n starred = {false},\n authored = {false},\n confirmed = {true},\n hidden = {false},\n private_publication = {false},\n abstract = {Although there is significant wave energy available world-wide, after almost 50 years of research and development no commercially successful technology has been developed. There are multiple potential reasons for this lack of clear progress, but it is suggested that one of these is the limited focus of the research in this area, which has focused on technologies based on buoyancy and diffraction forces. The need to investigate the use of lift forces for wave energy extraction is identified as deserving additional focus due to its different characteristics. A classification of concepts for lift-based wave energy converters is developed and used to assess the concepts that have been developed in this area. This classification is based on the method to create circulation required to generate lift forces and the motion of the body. A lift-based wave energy converter that uses a hydrofoil and continuous motion is identified as currently most promising. A further classification is also used to identify potential implementations of this configuration based on methods of controlling the rotation and circulation for operation in irregular waves. The paper concludes with a discussion of potential developments in this area.},\n bibtype = {inproceedings},\n author = {Folley, Matt and Whittaker, Trevor},\n booktitle = {13th European Wave and Tidal Energy Conference}\n}
\n
\n\n\n
\n Although there is significant wave energy available world-wide, after almost 50 years of research and development no commercially successful technology has been developed. There are multiple potential reasons for this lack of clear progress, but it is suggested that one of these is the limited focus of the research in this area, which has focused on technologies based on buoyancy and diffraction forces. The need to investigate the use of lift forces for wave energy extraction is identified as deserving additional focus due to its different characteristics. A classification of concepts for lift-based wave energy converters is developed and used to assess the concepts that have been developed in this area. This classification is based on the method to create circulation required to generate lift forces and the motion of the body. A lift-based wave energy converter that uses a hydrofoil and continuous motion is identified as currently most promising. A further classification is also used to identify potential implementations of this configuration based on methods of controlling the rotation and circulation for operation in irregular waves. The paper concludes with a discussion of potential developments in this area.\n
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\n \n\n \n \n \n \n \n Numerical benchmarking study of a Cycloidal Wave Energy Converter.\n \n \n \n\n\n \n Siegel, S., G.\n\n\n \n\n\n\n Renewable Energy, 134: 390-405. 4 2019.\n \n\n\n\n
\n\n\n\n \n\n \n \n doi\n  \n \n\n \n link\n  \n \n\n bibtex\n \n\n \n  \n \n abstract \n \n\n \n\n \n \n \n \n \n \n \n\n  \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n\n\n\n
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@article{\n title = {Numerical benchmarking study of a Cycloidal Wave Energy Converter},\n type = {article},\n year = {2019},\n keywords = {Benchmark,Cost of energy,Cycloidal wave energy converter,Mean annual power,Power matrix,Wave energy converter},\n pages = {390-405},\n volume = {134},\n month = {4},\n publisher = {Elsevier Ltd},\n day = {1},\n id = {21030703-dd96-3baa-b398-ca71114ad94b},\n created = {2020-04-08T16:15:44.031Z},\n accessed = {2020-04-08},\n file_attached = {false},\n profile_id = {80f79df7-70c4-3a7b-8290-0309ce34e49b},\n group_id = {a8cd9ed8-fd6b-32bd-a7ad-27ef75b1faca},\n last_modified = {2020-04-08T16:15:44.031Z},\n read = {false},\n starred = {false},\n authored = {false},\n confirmed = {false},\n hidden = {false},\n private_publication = {false},\n abstract = {A lift based Cycloidal Wave Energy Converter (CycWEC) was investigated using numerical simulations to estimate its mean annual power absorption. Based on the power absorption as well as size and weight estimates a number of performance measures were derived in order to compare this novel Wave Energy Converter (WEC) to other more established devices for which results have been published by Babarit et al. [1] using a similar benchmarking approach. Comparison of these measures with published data for eight more established WEC designs, including heaving buoy, oscillating water column and flap devices shows that the CycWEC performance in all metrics exceeds that of all other devices. Most importantly, the energy per mass of the CycWEC exceeds that of all other devices by more than an order of magnitude, indicating the potential of the CycWEC to significantly lower the Levelized Cost of Energy (LCoE) and reducing it to a level where the CycWEC can compete with other renewable energy sources like solar and wind.},\n bibtype = {article},\n author = {Siegel, Stefan G.},\n doi = {10.1016/j.renene.2018.11.041},\n journal = {Renewable Energy}\n}
\n
\n\n\n
\n A lift based Cycloidal Wave Energy Converter (CycWEC) was investigated using numerical simulations to estimate its mean annual power absorption. Based on the power absorption as well as size and weight estimates a number of performance measures were derived in order to compare this novel Wave Energy Converter (WEC) to other more established devices for which results have been published by Babarit et al. [1] using a similar benchmarking approach. Comparison of these measures with published data for eight more established WEC designs, including heaving buoy, oscillating water column and flap devices shows that the CycWEC performance in all metrics exceeds that of all other devices. Most importantly, the energy per mass of the CycWEC exceeds that of all other devices by more than an order of magnitude, indicating the potential of the CycWEC to significantly lower the Levelized Cost of Energy (LCoE) and reducing it to a level where the CycWEC can compete with other renewable energy sources like solar and wind.\n
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\n  \n 2016\n \n \n (1)\n \n \n
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\n \n\n \n \n \n \n \n \n Aerodynamic performance of a circulating airfoil section for Magnus systems via numerical simulation and flow visualization.\n \n \n \n \n\n\n \n Kazemi, S., A.; Nili-Ahmadabadi, M.; Sedaghat, A.; and Saghafian, M.\n\n\n \n\n\n\n Energy, 104: 1-15. 2016.\n \n\n\n\n
\n\n\n\n \n \n \"AerodynamicWebsite\n  \n \n\n \n \n doi\n  \n \n\n \n link\n  \n \n\n bibtex\n \n\n \n  \n \n abstract \n \n\n \n\n \n \n \n \n \n \n \n\n  \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n\n\n\n
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@article{\n title = {Aerodynamic performance of a circulating airfoil section for Magnus systems via numerical simulation and flow visualization},\n type = {article},\n year = {2016},\n keywords = {Flow visualization,Lift to drag ratio,Magnus effect,NACA0021 airfoil,Treadmill airfoil,Wind turbine},\n pages = {1-15},\n volume = {104},\n websites = {http://www.sciencedirect.com/science/article/pii/S0360544216303620},\n id = {d8c4c87b-d0bf-3d79-b928-bbfd64cd592d},\n created = {2020-04-07T10:18:58.928Z},\n file_attached = {false},\n profile_id = {191d98fc-2728-3909-a066-d0f90f3eaa56},\n group_id = {a8cd9ed8-fd6b-32bd-a7ad-27ef75b1faca},\n last_modified = {2020-04-07T10:18:58.928Z},\n read = {false},\n starred = {false},\n authored = {false},\n confirmed = {true},\n hidden = {false},\n source_type = {Journal Article},\n private_publication = {false},\n abstract = {Abstract The lift to drag ratio is the most determining factor in power efficiency of wind conversion systems such as wind turbines. The lift to drag ratio can be enhanced considerably using circulating airfoil shapes. In this research, the NACA0021 airfoil is modified and manufactured to form a treadmill like circulating shape. Aerodynamic performance of the treadmill shape is computationally and experimentally investigated. In the experiment, the smoke flow visualization is conducted in a small wind tunnel to study flow features such as separation and stagnation points. Computational method is based on the finite volume discretization of RANS (Reynolds Averaged Navier–Stokes) equations and the shear stress transport (k–ω SST (shear-stress transport)) turbulence modeling. Magnus effects are investigated under various speed ratios (speed of circulating surface to the wind speed) and several angles of attack. The numerical and flow visualization results reveal some main changes to flow features including full removal of separation zone above moving surfaces. At the speed ratio of 3, zero angle of attack and flow Reynolds number of 94,000, an impressive lift to drag ratio of 130 is obtained for the circulating airfoil whilst the maximum attainable value is merely 45 for the original NACA0021 airfoil.},\n bibtype = {article},\n author = {Kazemi, Seyed Ali and Nili-Ahmadabadi, Mahdi and Sedaghat, Ahmad and Saghafian, Mohsen},\n doi = {http://dx.doi.org/10.1016/j.energy.2016.03.115},\n journal = {Energy}\n}
\n
\n\n\n
\n Abstract The lift to drag ratio is the most determining factor in power efficiency of wind conversion systems such as wind turbines. The lift to drag ratio can be enhanced considerably using circulating airfoil shapes. In this research, the NACA0021 airfoil is modified and manufactured to form a treadmill like circulating shape. Aerodynamic performance of the treadmill shape is computationally and experimentally investigated. In the experiment, the smoke flow visualization is conducted in a small wind tunnel to study flow features such as separation and stagnation points. Computational method is based on the finite volume discretization of RANS (Reynolds Averaged Navier–Stokes) equations and the shear stress transport (k–ω SST (shear-stress transport)) turbulence modeling. Magnus effects are investigated under various speed ratios (speed of circulating surface to the wind speed) and several angles of attack. The numerical and flow visualization results reveal some main changes to flow features including full removal of separation zone above moving surfaces. At the speed ratio of 3, zero angle of attack and flow Reynolds number of 94,000, an impressive lift to drag ratio of 130 is obtained for the circulating airfoil whilst the maximum attainable value is merely 45 for the original NACA0021 airfoil.\n
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\n  \n 2015\n \n \n (2)\n \n \n
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\n \n\n \n \n \n \n \n Wave radiation of a cycloidal wave energy converter.\n \n \n \n\n\n \n Siegel, S., G.\n\n\n \n\n\n\n Applied Ocean Research, 49: 9-19. 2015.\n \n\n\n\n
\n\n\n\n \n\n \n \n doi\n  \n \n\n \n link\n  \n \n\n bibtex\n \n\n \n  \n \n abstract \n \n\n \n\n \n \n \n \n \n \n \n\n  \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n\n\n\n
\n
@article{\n title = {Wave radiation of a cycloidal wave energy converter},\n type = {article},\n year = {2015},\n keywords = {Cost of energy,Cycloidal turbine,Cycloidal wave energy converter,Deep ocean wave,Hydrofoil,Wave energy conversion,Wave radiation},\n pages = {9-19},\n volume = {49},\n id = {2b8515a5-ee83-323f-8034-d63c289c71eb},\n created = {2020-04-03T12:35:32.671Z},\n file_attached = {false},\n profile_id = {80f79df7-70c4-3a7b-8290-0309ce34e49b},\n group_id = {a8cd9ed8-fd6b-32bd-a7ad-27ef75b1faca},\n last_modified = {2020-04-03T12:38:43.228Z},\n read = {false},\n starred = {false},\n authored = {false},\n confirmed = {true},\n hidden = {false},\n private_publication = {false},\n abstract = {Numerical results from a three-dimensional radiation model are presented where a cycloidal wave energy converter (WEC) is interacting with an incoming straight crested airy wave. The radiation model was developed in response to experimental observations from 1:10 scale experiments which were conducted in the Texas A&M Offshore Technology Research center wave basin. These experiments were the first investigations involving a WEC where three dimensional wave radiation effects were present due to the fact that the span of the WEC was much smaller than the width of the basin. The radiation model predicted the observed surface wave patterns in the experiment well, and showed that radiation induced wave focusing increased the recoverable wave power beyond the two-dimensional predictions for small WEC spans, while approaching the two-dimensional limit for very large spans. The numerical model was subsequently used to investigate the sensitivity of the WEC to misalignment between the incoming waves and the WEC shaft as well as the impact of a gap in the blade setup of a double WEC. For misalignment, the loss in efficiency was found to be strongly dependent on the ratio between WEC span and incoming wavelength, where short spans (on the order of one wavelength or less) which are realistic for actual ocean deployment showed only minor reductions in efficiency, while very long spans were found to be more sensitive to misalignment. The blade gap in a double WEC setup was found to have a relatively minor effect (up to 30%) on efficiency. Efficiency was found to either increase or decrease depending on the size of the gap.},\n bibtype = {article},\n author = {Siegel, Stefan G.},\n doi = {10.1016/j.apor.2014.10.006},\n journal = {Applied Ocean Research}\n}
\n
\n\n\n
\n Numerical results from a three-dimensional radiation model are presented where a cycloidal wave energy converter (WEC) is interacting with an incoming straight crested airy wave. The radiation model was developed in response to experimental observations from 1:10 scale experiments which were conducted in the Texas A&M Offshore Technology Research center wave basin. These experiments were the first investigations involving a WEC where three dimensional wave radiation effects were present due to the fact that the span of the WEC was much smaller than the width of the basin. The radiation model predicted the observed surface wave patterns in the experiment well, and showed that radiation induced wave focusing increased the recoverable wave power beyond the two-dimensional predictions for small WEC spans, while approaching the two-dimensional limit for very large spans. The numerical model was subsequently used to investigate the sensitivity of the WEC to misalignment between the incoming waves and the WEC shaft as well as the impact of a gap in the blade setup of a double WEC. For misalignment, the loss in efficiency was found to be strongly dependent on the ratio between WEC span and incoming wavelength, where short spans (on the order of one wavelength or less) which are realistic for actual ocean deployment showed only minor reductions in efficiency, while very long spans were found to be more sensitive to misalignment. The blade gap in a double WEC setup was found to have a relatively minor effect (up to 30%) on efficiency. Efficiency was found to either increase or decrease depending on the size of the gap.\n
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\n \n\n \n \n \n \n \n Ship propulsion in waves by actively controlled flapping foils.\n \n \n \n\n\n \n Belibassakis, K., A.; and Filippas, E., S.\n\n\n \n\n\n\n Applied Ocean Research, 52: 1-11. 8 2015.\n \n\n\n\n
\n\n\n\n \n\n \n \n doi\n  \n \n\n \n link\n  \n \n\n bibtex\n \n\n \n  \n \n abstract \n \n\n \n\n \n \n \n \n \n \n \n\n  \n \n \n \n \n \n \n \n \n \n \n \n \n\n\n\n
\n
@article{\n title = {Ship propulsion in waves by actively controlled flapping foils},\n type = {article},\n year = {2015},\n keywords = {Active control,Flapping foils,Free-surface effects,Random waves,Unsteady thruster},\n pages = {1-11},\n volume = {52},\n month = {8},\n publisher = {Elsevier Ltd},\n day = {1},\n id = {39da6bbc-f077-3f83-b4d1-d311c7ae3e55},\n created = {2020-04-08T16:10:18.937Z},\n accessed = {2020-04-08},\n file_attached = {false},\n profile_id = {80f79df7-70c4-3a7b-8290-0309ce34e49b},\n group_id = {a8cd9ed8-fd6b-32bd-a7ad-27ef75b1faca},\n last_modified = {2020-05-07T08:36:19.839Z},\n read = {false},\n starred = {false},\n authored = {false},\n confirmed = {true},\n hidden = {false},\n private_publication = {false},\n abstract = {Flapping wings located beneath or to the side of the hull of the ship are investigated as unsteady thrusters, augmenting ship propulsion in waves. The main arrangement consists of horizontal wing(s) in vertical oscillatory motion which is induced by ship heave and pitch, while rotation about the wing pivot axis is actively controlled. In this work we investigate the energy extraction by the system operating in irregular wave conditions and its performance concerning direct conversion to propulsive thrust. More specifically, we consider operation of the flapping foil in waves characterised by a spectrum, corresponding to specific sea state, taking into account the coupling between the hull and the flapping foil dynamics. The effect of the wavy free surface is accounted for through the satisfaction of the corresponding boundary conditions and the consideration of the wave velocity on the formation of the incident flow. Numerical results concerning thrust and power coefficients are presented, indicating that significant thrust can be produced under general operating conditions. The present work can be exploited for the design and optimum control of such systems extracting energy from sea waves for augmenting marine propulsion in rough seas, with simultaneous reduction of ship responses offering also dynamic stabilisation.},\n bibtype = {article},\n author = {Belibassakis, K. A. and Filippas, E. S.},\n doi = {10.1016/j.apor.2015.04.009},\n journal = {Applied Ocean Research}\n}
\n
\n\n\n
\n Flapping wings located beneath or to the side of the hull of the ship are investigated as unsteady thrusters, augmenting ship propulsion in waves. The main arrangement consists of horizontal wing(s) in vertical oscillatory motion which is induced by ship heave and pitch, while rotation about the wing pivot axis is actively controlled. In this work we investigate the energy extraction by the system operating in irregular wave conditions and its performance concerning direct conversion to propulsive thrust. More specifically, we consider operation of the flapping foil in waves characterised by a spectrum, corresponding to specific sea state, taking into account the coupling between the hull and the flapping foil dynamics. The effect of the wavy free surface is accounted for through the satisfaction of the corresponding boundary conditions and the consideration of the wave velocity on the formation of the incident flow. Numerical results concerning thrust and power coefficients are presented, indicating that significant thrust can be produced under general operating conditions. The present work can be exploited for the design and optimum control of such systems extracting energy from sea waves for augmenting marine propulsion in rough seas, with simultaneous reduction of ship responses offering also dynamic stabilisation.\n
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\n  \n 2014\n \n \n (2)\n \n \n
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\n \n\n \n \n \n \n \n Analysis of a cycloidal wave energy converter using unsteady Reynolds averaged Navier-Stokes simulation.\n \n \n \n\n\n \n Caskey, C., J.\n\n\n \n\n\n\n 2014.\n \n\n\n\n
\n\n\n\n \n\n \n\n \n link\n  \n \n\n bibtex\n \n\n \n\n \n\n \n \n \n \n \n \n \n\n  \n \n \n\n\n\n
\n
@misc{\n title = {Analysis of a cycloidal wave energy converter using unsteady Reynolds averaged Navier-Stokes simulation},\n type = {misc},\n year = {2014},\n id = {e3ecbc4b-5a6d-3848-b639-797a0dfc98f3},\n created = {2020-04-08T15:56:54.855Z},\n accessed = {2020-04-08},\n file_attached = {false},\n profile_id = {80f79df7-70c4-3a7b-8290-0309ce34e49b},\n group_id = {a8cd9ed8-fd6b-32bd-a7ad-27ef75b1faca},\n last_modified = {2020-04-08T15:56:54.855Z},\n read = {false},\n starred = {false},\n authored = {false},\n confirmed = {false},\n hidden = {false},\n private_publication = {false},\n bibtype = {misc},\n author = {Caskey, Christopher J.}\n}
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\n \n\n \n \n \n \n \n Wave climate scatter performance of a cycloidal wave energy converter.\n \n \n \n\n\n \n Siegel, S., G.\n\n\n \n\n\n\n Applied Ocean Research, 48: 331-343. 10 2014.\n \n\n\n\n
\n\n\n\n \n\n \n \n doi\n  \n \n\n \n link\n  \n \n\n bibtex\n \n\n \n  \n \n abstract \n \n\n \n\n \n \n \n \n \n \n \n\n  \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n\n\n\n
\n
@article{\n title = {Wave climate scatter performance of a cycloidal wave energy converter},\n type = {article},\n year = {2014},\n keywords = {Cost of energy,Cycloidal turbine,Cycloidal wave energy converter,Deep ocean wave,Wave energy conversion,Wave scatter diagram},\n pages = {331-343},\n volume = {48},\n month = {10},\n publisher = {Elsevier Ltd},\n day = {1},\n id = {62ab8fd8-fa4f-374a-afa5-5575020c19e6},\n created = {2020-04-08T16:18:55.559Z},\n accessed = {2020-04-08},\n file_attached = {false},\n profile_id = {80f79df7-70c4-3a7b-8290-0309ce34e49b},\n group_id = {a8cd9ed8-fd6b-32bd-a7ad-27ef75b1faca},\n last_modified = {2020-04-17T13:09:27.562Z},\n read = {false},\n starred = {false},\n authored = {false},\n confirmed = {false},\n hidden = {false},\n private_publication = {false},\n abstract = {A lift based cycloidal wave energy converter (WEC) was investigated using potential flow numerical simulations in combination with viscous loss estimates based on published hydrofoil data. This type of wave energy converter consists of a shaft with one or more hydrofoils attached eccentrically at a radius. The main shaft is aligned parallel to the wave crests and submerged at a fixed depth. The operation of the WEC as a wave-to-shaft energy converter interacting with straight crested waves was estimated for an actual ocean wave climate. The climate chosen was the climate recorded by a buoy off the north-east shore of Oahu/Hawaii, which was a typical moderate wave climate featuring an average annual wave power PW=17kWh/m of wave crest. The impact of the design variables radius, chord, span and maximum generator power on the average annual shaft energy yield, capacity factor and power production time fraction were explored. In the selected wave climate, a radius R=5m, chord C=5m and span of S=60m along with a maximum generator power of PG=1.25MW were found to be optimal in terms of annual shaft energy yield. At the design point, the CycWEC achieved a wave-to-shaft power efficiency of 70%. In the annual average, 40% of the incoming wave energy was converted to shaft energy, and a capacity factor of 42% was achieved. These numbers exceeded the typical performance of competing renewables like wind power, and demonstrated that the WEC was able to convert wave energy to shaft energy efficiently for a range of wave periods and wave heights as encountered in a typical wave climate.},\n bibtype = {article},\n author = {Siegel, Stefan G.},\n doi = {10.1016/j.apor.2014.10.008},\n journal = {Applied Ocean Research}\n}
\n
\n\n\n
\n A lift based cycloidal wave energy converter (WEC) was investigated using potential flow numerical simulations in combination with viscous loss estimates based on published hydrofoil data. This type of wave energy converter consists of a shaft with one or more hydrofoils attached eccentrically at a radius. The main shaft is aligned parallel to the wave crests and submerged at a fixed depth. The operation of the WEC as a wave-to-shaft energy converter interacting with straight crested waves was estimated for an actual ocean wave climate. The climate chosen was the climate recorded by a buoy off the north-east shore of Oahu/Hawaii, which was a typical moderate wave climate featuring an average annual wave power PW=17kWh/m of wave crest. The impact of the design variables radius, chord, span and maximum generator power on the average annual shaft energy yield, capacity factor and power production time fraction were explored. In the selected wave climate, a radius R=5m, chord C=5m and span of S=60m along with a maximum generator power of PG=1.25MW were found to be optimal in terms of annual shaft energy yield. At the design point, the CycWEC achieved a wave-to-shaft power efficiency of 70%. In the annual average, 40% of the incoming wave energy was converted to shaft energy, and a capacity factor of 42% was achieved. These numbers exceeded the typical performance of competing renewables like wind power, and demonstrated that the WEC was able to convert wave energy to shaft energy efficiently for a range of wave periods and wave heights as encountered in a typical wave climate.\n
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\n  \n 2013\n \n \n (2)\n \n \n
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\n \n \n
\n \n\n \n \n \n \n \n Irregular deep ocean wave energy attenuation using a cycloidal wave energy converter.\n \n \n \n\n\n \n Jeans, T.; Fagley, C., P.; Siegel, S., G.; and Seidel, J., J.\n\n\n \n\n\n\n International Journal of Marine Energy. 2013.\n \n\n\n\n
\n\n\n\n \n\n \n \n doi\n  \n \n\n \n link\n  \n \n\n bibtex\n \n\n \n  \n \n abstract \n \n\n \n\n \n \n \n \n \n \n \n\n  \n \n \n \n \n \n \n \n \n \n \n\n\n\n
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@article{\n title = {Irregular deep ocean wave energy attenuation using a cycloidal wave energy converter},\n type = {article},\n year = {2013},\n keywords = {Cycloidal wave energy converter,Feedback flow-control,Irregular deep ocean wave,Ocean wave energy conversion},\n id = {b48647b9-9a30-376c-ade6-2406b6ea2662},\n created = {2020-04-03T12:32:36.325Z},\n file_attached = {false},\n profile_id = {80f79df7-70c4-3a7b-8290-0309ce34e49b},\n group_id = {a8cd9ed8-fd6b-32bd-a7ad-27ef75b1faca},\n last_modified = {2020-04-17T13:09:27.346Z},\n read = {false},\n starred = {false},\n authored = {false},\n confirmed = {true},\n hidden = {false},\n private_publication = {false},\n abstract = {The performance of a lift based wave energy converter in unidirectional irregular deep ocean waves is investigated. The energy converter consists of two hydrofoils attached parallel to a horizontal main shaft at a radius. The main shaft is aligned parallel to the wave crests and submerged at a fixed depth. The local flow field induced by the incident wave will cause the hydrofoils to rotate about the main shaft. The orientation of each hydrofoil is adjusted to produce the desired level of bound circulation. The energy converter and incident wave field are modeled using potential flow theory. The wave field is assumed to be long-crested and the hydrofoil span infinitely long, thereby the resulting flow field is two-dimensional. Each hydrofoil is modeled as a point vortex moving under a free surface. The irregular ocean wave is modeled by linear superposition of a finite number of regular wave components. The amplitude and frequency of each component is determined based on a Bretschneider spectrum. The hydrofoil position and bound circulation are controlled using a sensor located up-wave of the device and wave state estimator. The results demonstrate the converter's ability to effectively extract energy from multiple wave components simultaneously. Inviscid hydrodynamic efficiencies for incident wave fields consisting of 7 and 10 regular wave components were 85% and 77%, respectively. © 2013 Elsevier Ltd. All rights reserved.},\n bibtype = {article},\n author = {Jeans, Tiger and Fagley, Casey P. and Siegel, Stefan G. and Seidel, Jürgen J.},\n doi = {10.1016/j.ijome.2013.06.001},\n journal = {International Journal of Marine Energy}\n}
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\n The performance of a lift based wave energy converter in unidirectional irregular deep ocean waves is investigated. The energy converter consists of two hydrofoils attached parallel to a horizontal main shaft at a radius. The main shaft is aligned parallel to the wave crests and submerged at a fixed depth. The local flow field induced by the incident wave will cause the hydrofoils to rotate about the main shaft. The orientation of each hydrofoil is adjusted to produce the desired level of bound circulation. The energy converter and incident wave field are modeled using potential flow theory. The wave field is assumed to be long-crested and the hydrofoil span infinitely long, thereby the resulting flow field is two-dimensional. Each hydrofoil is modeled as a point vortex moving under a free surface. The irregular ocean wave is modeled by linear superposition of a finite number of regular wave components. The amplitude and frequency of each component is determined based on a Bretschneider spectrum. The hydrofoil position and bound circulation are controlled using a sensor located up-wave of the device and wave state estimator. The results demonstrate the converter's ability to effectively extract energy from multiple wave components simultaneously. Inviscid hydrodynamic efficiencies for incident wave fields consisting of 7 and 10 regular wave components were 85% and 77%, respectively. © 2013 Elsevier Ltd. All rights reserved.\n
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\n \n\n \n \n \n \n \n 3D Efficiency analysis of Cycloidal wave energy converters in oblique wave fields.\n \n \n \n\n\n \n Fagley, C., P.; Siegel, S., G.; Seidel, J., J.; and Schmittner, C.\n\n\n \n\n\n\n In Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE, volume 8, 2013. \n \n\n\n\n
\n\n\n\n \n\n \n \n doi\n  \n \n\n \n link\n  \n \n\n bibtex\n \n\n \n  \n \n abstract \n \n\n \n\n \n \n \n \n \n \n \n\n  \n \n \n\n\n\n
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@inproceedings{\n title = {3D Efficiency analysis of Cycloidal wave energy converters in oblique wave fields},\n type = {inproceedings},\n year = {2013},\n volume = {8},\n id = {31cbee08-165e-3870-adf5-2ce04c1a1c5d},\n created = {2020-04-08T16:04:26.526Z},\n accessed = {2020-04-08},\n file_attached = {false},\n profile_id = {80f79df7-70c4-3a7b-8290-0309ce34e49b},\n group_id = {a8cd9ed8-fd6b-32bd-a7ad-27ef75b1faca},\n last_modified = {2020-04-17T13:09:27.397Z},\n read = {false},\n starred = {false},\n authored = {false},\n confirmed = {false},\n hidden = {false},\n private_publication = {false},\n abstract = {Numerical results from a 3D diffraction model are presented where a Cycloidal Wave Energy Converter (CycWEC) is interacting with an incoming straight crested Airy Wave. The diffraction model was developed in response to experimental observations from 1:10 scale experiments which were conducted in the Texas A&M Offshore Technology Research center wave basin. These experiments were the first investigations involving a CycWEC where three dimensional wave diffraction effects were present due to the fact that the span of the CycWEC was much smaller than the width of the basin. The diffraction model predicted the observed surface wave patterns in the experiment well, and showed that diffraction induced wave focusing increased the recoverable wave power beyond the 2D predictions for small CycWEC spans, while approaching the 2D limit for very large spans. The numerical model was subsequently used to estimate the sensitivity of the CycWEC to misalignment between the incoming waves and the WEC shaft. The loss in efficiency was found to be strongly dependent on the ratio between WEC span and incoming wavelength, where short spans (on the order of one wave length or less) which are realistic for actual ocean deployment showed only minor reductions in efficiency, while very long spans were found to be more sensitive to misalignment. © 2013 by ASME.},\n bibtype = {inproceedings},\n author = {Fagley, Casey P. and Siegel, Stefan G. and Seidel, Jürgen J. and Schmittner, Christian},\n doi = {10.1115/OMAE2013-10876},\n booktitle = {Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE}\n}
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\n Numerical results from a 3D diffraction model are presented where a Cycloidal Wave Energy Converter (CycWEC) is interacting with an incoming straight crested Airy Wave. The diffraction model was developed in response to experimental observations from 1:10 scale experiments which were conducted in the Texas A&M Offshore Technology Research center wave basin. These experiments were the first investigations involving a CycWEC where three dimensional wave diffraction effects were present due to the fact that the span of the CycWEC was much smaller than the width of the basin. The diffraction model predicted the observed surface wave patterns in the experiment well, and showed that diffraction induced wave focusing increased the recoverable wave power beyond the 2D predictions for small CycWEC spans, while approaching the 2D limit for very large spans. The numerical model was subsequently used to estimate the sensitivity of the CycWEC to misalignment between the incoming waves and the WEC shaft. The loss in efficiency was found to be strongly dependent on the ratio between WEC span and incoming wavelength, where short spans (on the order of one wave length or less) which are realistic for actual ocean deployment showed only minor reductions in efficiency, while very long spans were found to be more sensitive to misalignment. © 2013 by ASME.\n
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\n  \n 2012\n \n \n (1)\n \n \n
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\n \n\n \n \n \n \n \n Computational investigation of irregular wave cancelation using a Cycloidal Wave Energy Converter.\n \n \n \n\n\n \n Fagley, C., P.; Seidel, J., J.; and Siegel, S., G.\n\n\n \n\n\n\n In Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE, volume 7, pages 351-358, 2012. \n \n\n\n\n
\n\n\n\n \n\n \n \n doi\n  \n \n\n \n link\n  \n \n\n bibtex\n \n\n \n  \n \n abstract \n \n\n \n\n \n \n \n \n \n \n \n\n  \n \n \n\n\n\n
\n
@inproceedings{\n title = {Computational investigation of irregular wave cancelation using a Cycloidal Wave Energy Converter},\n type = {inproceedings},\n year = {2012},\n pages = {351-358},\n volume = {7},\n id = {ede79394-9c6a-3654-bf06-0f3c41dcd30a},\n created = {2020-04-08T16:01:47.013Z},\n accessed = {2020-04-08},\n file_attached = {false},\n profile_id = {80f79df7-70c4-3a7b-8290-0309ce34e49b},\n group_id = {a8cd9ed8-fd6b-32bd-a7ad-27ef75b1faca},\n last_modified = {2020-04-08T16:01:47.013Z},\n read = {false},\n starred = {false},\n authored = {false},\n confirmed = {false},\n hidden = {false},\n private_publication = {false},\n abstract = {The ability of a Cycloidal Wave Energy Converter (CycWEC) to cancel irregular deep ocean waves is investigated in a time integrated, inviscid potential flow simulation. A CycWEC consists of one or more hydrofoils attached eccentrically to a shaft that is aligned parallel to the incoming waves. The entire device is fully submerged in operation. A Bretschneider spectrum with 40 discrete components is used to model an irregular wave environment in the simulations. A sensor placed up-wave of the CycWEC measures the incoming wave height and provides a signal for the wave state estimator, a non-causal Hilbert transformation, to estimate the instantaneous frequency, phase and amplitude of the irregular wave pattern. A linear control scheme which proportionally controls hydrofoil pitch and compensates for phase delays is adopted. Efficiency for the design Bretschneider spectrum shows more than 99% efficiency, while non-optimum, off design operating conditions still maintain more than 85% efficiency. These results are in agreement with concurrent experimental results obtained at a 1:300 scale. Copyright © 2012 by ASME.},\n bibtype = {inproceedings},\n author = {Fagley, Casey P. and Seidel, Jürgen J. and Siegel, Stefan G.},\n doi = {10.1115/OMAE2012-83434},\n booktitle = {Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE}\n}
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\n The ability of a Cycloidal Wave Energy Converter (CycWEC) to cancel irregular deep ocean waves is investigated in a time integrated, inviscid potential flow simulation. A CycWEC consists of one or more hydrofoils attached eccentrically to a shaft that is aligned parallel to the incoming waves. The entire device is fully submerged in operation. A Bretschneider spectrum with 40 discrete components is used to model an irregular wave environment in the simulations. A sensor placed up-wave of the CycWEC measures the incoming wave height and provides a signal for the wave state estimator, a non-causal Hilbert transformation, to estimate the instantaneous frequency, phase and amplitude of the irregular wave pattern. A linear control scheme which proportionally controls hydrofoil pitch and compensates for phase delays is adopted. Efficiency for the design Bretschneider spectrum shows more than 99% efficiency, while non-optimum, off design operating conditions still maintain more than 85% efficiency. These results are in agreement with concurrent experimental results obtained at a 1:300 scale. Copyright © 2012 by ASME.\n
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\n  \n 2011\n \n \n (4)\n \n \n
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\n \n\n \n \n \n \n \n Irregular Deep Ocean Wave Energy Conversion Using a Cycloidal Wave Energy Converter.\n \n \n \n\n\n \n Jeans, T.; Fagley, C., P.; Siegel, S., G.; and Seidel, J., J.\n\n\n \n\n\n\n In EWTEC 2011 Proceedings, 2011. \n \n\n\n\n
\n\n\n\n \n\n \n\n \n link\n  \n \n\n bibtex\n \n\n \n  \n \n abstract \n \n\n \n\n \n \n \n \n \n \n \n\n  \n \n \n \n \n \n \n \n \n \n \n \n \n\n\n\n
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@inproceedings{\n title = {Irregular Deep Ocean Wave Energy Conversion Using a Cycloidal Wave Energy Converter},\n type = {inproceedings},\n year = {2011},\n keywords = {Cycloidal Wave Energy Converter,Feedback flowcontrol,Irregular Deep,Ocean Wave,Ocean Wave Energy Conversion},\n id = {0e2491df-0a4b-3f93-8da2-463cfd8d0b55},\n created = {2020-04-03T12:35:32.813Z},\n file_attached = {false},\n profile_id = {80f79df7-70c4-3a7b-8290-0309ce34e49b},\n group_id = {a8cd9ed8-fd6b-32bd-a7ad-27ef75b1faca},\n last_modified = {2020-04-17T13:09:27.563Z},\n read = {false},\n starred = {false},\n authored = {false},\n confirmed = {true},\n hidden = {false},\n private_publication = {false},\n abstract = {The performance of a lift based wave energy converter in unidirectional irregular deep ocean waves is investigated. The energy converter consists of two hydrofoils attached parallel to a horizontal main shaft at a radius. The main shaft is aligned parallel to the wave crests and submerged at a fixed depth. The local flow field induced by the incident wave will cause the hydrofoils to rotate about the main shaft. The orientation of each hydrofoil is adjusted to produce the desired level of bound circulation. The energy converter and incident wave field are modeled using potential flow theory. The wave field is assumed to be long-crested and the hydrofoil span infinitely long, thereby the resulting flow field is two-dimensional. Each hydrofoil is modeled as a point vortex moving under a free surface. The irregular ocean wave is modeled by linear superposition of a finite number of regular wave components. The amplitude and frequency of each component is determined based on a Bretschneider spectrum. The hydrofoil position and bound circulation are controlled using a sensor located up-wave of the device and wave state estimator. The results demonstrate the converter’s ability to effectively extract energy from multiple wave components simultaneously. Device efficiencies for incident wave fields consisting of 7 and 10 regular wave components were 85% and 77%, respectively.},\n bibtype = {inproceedings},\n author = {Jeans, Tiger and Fagley, Casey P. and Siegel, Stefan G. and Seidel, Jürgen J.},\n booktitle = {EWTEC 2011 Proceedings}\n}
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\n The performance of a lift based wave energy converter in unidirectional irregular deep ocean waves is investigated. The energy converter consists of two hydrofoils attached parallel to a horizontal main shaft at a radius. The main shaft is aligned parallel to the wave crests and submerged at a fixed depth. The local flow field induced by the incident wave will cause the hydrofoils to rotate about the main shaft. The orientation of each hydrofoil is adjusted to produce the desired level of bound circulation. The energy converter and incident wave field are modeled using potential flow theory. The wave field is assumed to be long-crested and the hydrofoil span infinitely long, thereby the resulting flow field is two-dimensional. Each hydrofoil is modeled as a point vortex moving under a free surface. The irregular ocean wave is modeled by linear superposition of a finite number of regular wave components. The amplitude and frequency of each component is determined based on a Bretschneider spectrum. The hydrofoil position and bound circulation are controlled using a sensor located up-wave of the device and wave state estimator. The results demonstrate the converter’s ability to effectively extract energy from multiple wave components simultaneously. Device efficiencies for incident wave fields consisting of 7 and 10 regular wave components were 85% and 77%, respectively.\n
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\n \n\n \n \n \n \n \n Experimental Wave Cancellation using a Cycloidal Wave Energy Converter.\n \n \n \n\n\n \n Siegel, S., G.; Fagley, C., P.; Römer, M.; and McLaughlin, T., E.\n\n\n \n\n\n\n In EWTEC 2011 Proceedings, 2011. \n \n\n\n\n
\n\n\n\n \n\n \n\n \n link\n  \n \n\n bibtex\n \n\n \n  \n \n abstract \n \n\n \n\n \n \n \n \n \n \n \n\n  \n \n \n \n \n \n \n \n \n \n \n \n \n\n\n\n
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@inproceedings{\n title = {Experimental Wave Cancellation using a Cycloidal Wave Energy Converter},\n type = {inproceedings},\n year = {2011},\n keywords = {Cycloidal Wave Energy Converter,Deep Ocean Wave,Feedback Control,Wave Tunnel,Wave termination},\n id = {5abbd9b3-f6b0-3663-885e-b4dd4a3c60fb},\n created = {2020-04-03T12:35:32.897Z},\n file_attached = {false},\n profile_id = {80f79df7-70c4-3a7b-8290-0309ce34e49b},\n group_id = {a8cd9ed8-fd6b-32bd-a7ad-27ef75b1faca},\n last_modified = {2020-04-17T13:09:27.483Z},\n read = {false},\n starred = {false},\n authored = {false},\n confirmed = {true},\n hidden = {false},\n private_publication = {false},\n abstract = {The ability of a Cycloidal Wave Energy Converter (CycWEC) to cancel deep ocean waves is investigated in a wave tunnel experiment. A CycWEC consists of one or more hydrofoils attached eccentrically to a shaft that is aligned parallel to the incoming waves. The entire device is fully submerged in operation. Wave cancellation requires synchronization of the rotation of the CycWEC with the incoming waves, as well as adjustment of the pitch angle of the blades in proportion to the wave height. We describe the development of a state estimator and controller that achieves this objective, using the signal from a resistive wave gage located up–wave of the CycWEC as input. The CycWEC model used for the present investigations features two blades that are adjustable in pitch in real time. The performance of the control scheme is demonstrated over a range of wave heights as well as periods. We achieve wave cancellation efficiencies as determined by wave measurements of greater than 85% for the majority of the cases investigated, with wave periods varying from 0.4s to 0.75s and wave heights ranging from ≈ 5mmpk to ≈ 20mmpk at a model scale of 1:300. The range of wave periods investigated covers both deep and intermediate water waves, while the wave heights range from small height linear Airy to 3rd order Stokes waves. We thus conclude that the CycWEC can efficiently interact with waves of varying height and frequency, which is in good agreement with earlier results obtained from numerical simulations.},\n bibtype = {inproceedings},\n author = {Siegel, Stefan G. and Fagley, Casey P. and Römer, Marcus and McLaughlin, Thomas E},\n booktitle = {EWTEC 2011 Proceedings}\n}
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\n The ability of a Cycloidal Wave Energy Converter (CycWEC) to cancel deep ocean waves is investigated in a wave tunnel experiment. A CycWEC consists of one or more hydrofoils attached eccentrically to a shaft that is aligned parallel to the incoming waves. The entire device is fully submerged in operation. Wave cancellation requires synchronization of the rotation of the CycWEC with the incoming waves, as well as adjustment of the pitch angle of the blades in proportion to the wave height. We describe the development of a state estimator and controller that achieves this objective, using the signal from a resistive wave gage located up–wave of the CycWEC as input. The CycWEC model used for the present investigations features two blades that are adjustable in pitch in real time. The performance of the control scheme is demonstrated over a range of wave heights as well as periods. We achieve wave cancellation efficiencies as determined by wave measurements of greater than 85% for the majority of the cases investigated, with wave periods varying from 0.4s to 0.75s and wave heights ranging from ≈ 5mmpk to ≈ 20mmpk at a model scale of 1:300. The range of wave periods investigated covers both deep and intermediate water waves, while the wave heights range from small height linear Airy to 3rd order Stokes waves. We thus conclude that the CycWEC can efficiently interact with waves of varying height and frequency, which is in good agreement with earlier results obtained from numerical simulations.\n
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\n \n\n \n \n \n \n \n Deep ocean wave energy conversion using a cycloidal turbine.\n \n \n \n\n\n \n Siegel, S., G.; Jeans, T.; and McLaughlin, T., E.\n\n\n \n\n\n\n Applied Ocean Research, 33(2): 110-119. 2011.\n \n\n\n\n
\n\n\n\n \n\n \n \n doi\n  \n \n\n \n link\n  \n \n\n bibtex\n \n\n \n  \n \n abstract \n \n\n \n\n \n \n \n \n \n \n \n\n  \n \n \n \n \n \n \n \n \n\n\n\n
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@article{\n title = {Deep ocean wave energy conversion using a cycloidal turbine},\n type = {article},\n year = {2011},\n keywords = {Cycloidal turbine,Deep ocean wave,Wave energy conversion},\n pages = {110-119},\n volume = {33},\n id = {c55a5433-1d58-31d1-8213-05bb36f6e5ca},\n created = {2020-04-03T12:35:32.898Z},\n file_attached = {false},\n profile_id = {80f79df7-70c4-3a7b-8290-0309ce34e49b},\n group_id = {a8cd9ed8-fd6b-32bd-a7ad-27ef75b1faca},\n last_modified = {2020-04-03T12:38:43.513Z},\n read = {false},\n starred = {false},\n authored = {false},\n confirmed = {true},\n hidden = {false},\n private_publication = {false},\n abstract = {A lift based wave energy converter, namely, a cycloidal turbine, is investigated. This type of wave energy converter consists of a shaft with one or more hydrofoils attached eccentrically at a radius. The main shaft is aligned parallel to the wave crests and submerged at a fixed depth. In the two-dimensional limit, i.e. for large spans of the hydrofoil (or an array of these), the geometry of the converter is suitable for wave termination of straight crested Airy waves. Results from two-dimensional potential flow simulations, with thin hydrofoils modeled as either a point vortex or discrete vortex panel, are presented. The operation of the cycloidal turbine both as a wave generator as well as a wave-to-shaft energy converter interacting with a linear Airy wave is demonstrated. The impact on the performance of the converter for design parameters such as device size, submergence depth, and number of hydrofoils is shown. For optimal parameter choices, simulation results demonstrate inviscid energy conversion efficiencies of more than 99% of the incoming wave energy to shaft energy. This is achieved using feedback control to synchronize the rotational rate, blade pitch angle, and phase of the cycloidal wave energy converter to the incoming wave. While complete termination of the incoming wave is shown, the remainder of the energy is lost to harmonic waves traveling in the up-wave and down-wave directions. © 2011 Elsevier Ltd.},\n bibtype = {article},\n author = {Siegel, Stefan G. and Jeans, Tiger and McLaughlin, Thomas E},\n doi = {10.1016/j.apor.2011.01.004},\n journal = {Applied Ocean Research},\n number = {2}\n}
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\n A lift based wave energy converter, namely, a cycloidal turbine, is investigated. This type of wave energy converter consists of a shaft with one or more hydrofoils attached eccentrically at a radius. The main shaft is aligned parallel to the wave crests and submerged at a fixed depth. In the two-dimensional limit, i.e. for large spans of the hydrofoil (or an array of these), the geometry of the converter is suitable for wave termination of straight crested Airy waves. Results from two-dimensional potential flow simulations, with thin hydrofoils modeled as either a point vortex or discrete vortex panel, are presented. The operation of the cycloidal turbine both as a wave generator as well as a wave-to-shaft energy converter interacting with a linear Airy wave is demonstrated. The impact on the performance of the converter for design parameters such as device size, submergence depth, and number of hydrofoils is shown. For optimal parameter choices, simulation results demonstrate inviscid energy conversion efficiencies of more than 99% of the incoming wave energy to shaft energy. This is achieved using feedback control to synchronize the rotational rate, blade pitch angle, and phase of the cycloidal wave energy converter to the incoming wave. While complete termination of the incoming wave is shown, the remainder of the energy is lost to harmonic waves traveling in the up-wave and down-wave directions. © 2011 Elsevier Ltd.\n
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\n \n\n \n \n \n \n \n Cancellation of non-harmonic waves using a cycloidal turbine.\n \n \n \n\n\n \n Imamura, J., T.; Siegel, S., G.; Fagley, C., P.; and McLaughlin, T., E.\n\n\n \n\n\n\n In Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE, volume 5, pages 385-393, 2011. \n \n\n\n\n
\n\n\n\n \n\n \n \n doi\n  \n \n\n \n link\n  \n \n\n bibtex\n \n\n \n  \n \n abstract \n \n\n \n\n \n \n \n \n \n \n \n\n  \n \n \n\n\n\n
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@inproceedings{\n title = {Cancellation of non-harmonic waves using a cycloidal turbine},\n type = {inproceedings},\n year = {2011},\n pages = {385-393},\n volume = {5},\n id = {b2c57dcd-5858-3def-9f31-a42d1d295dc8},\n created = {2020-04-08T16:07:14.748Z},\n accessed = {2020-04-08},\n file_attached = {false},\n profile_id = {80f79df7-70c4-3a7b-8290-0309ce34e49b},\n group_id = {a8cd9ed8-fd6b-32bd-a7ad-27ef75b1faca},\n last_modified = {2020-04-17T13:09:27.583Z},\n read = {false},\n starred = {false},\n authored = {false},\n confirmed = {false},\n hidden = {false},\n private_publication = {false},\n abstract = {We computationally investigate the ability of a cycloidal turbine to cancel two-dimensional non-harmonic waves in deep water. A cycloidal turbine employs the same geometry as the well established Cycloidal or Voith-Schneider Propeller. It consists of a shaft and one or more hydrofoils that are attached eccentrically to the main shaft and can be independently adjusted in pitch angle as the cycloidal turbine rotates. We simulate the cycloidal turbine interaction with incoming waves by viewing the turbine as a wave generator superimposed with the incoming flow. The generated waves ideally are 180° out of phase and cancel the incoming wave downstream of the turbine. The upstream wave is very small as generation of single-sided waves is a characteristic of the cycloidal turbine as has been shown in prior work. The superposition of the incoming wave and generated wave is investigated in the far-field and we model the hydrofoil as a point vortex. This model has previously been used to successfully terminate regular deep water waves as well as intermediate depth water waves. We explore the ability of this model to cancel nonharmonic waves. Near complete cancellation is possible for a non-harmonic wave with components designed to match those generated by the cycloidal turbine for specified parameters. Cancellation of a specific wave component of a multi-component system is also shown. Also, step changes in the device operating parameters of circulation strength, rotation rate, and submergence depth are explored to give insight to the cycloidal turbine response characteristics and adaptability to changes in incoming waves. Based on these studies a linear, time-invarient (LTI) model is developed which captures the steady state wave frequency response. Such a model can be used for control development in future efforts to efficiently cancel more complex incoming waves. Copyright © 2011 by ASME.},\n bibtype = {inproceedings},\n author = {Imamura, John T. and Siegel, Stefan G. and Fagley, Casey P. and McLaughlin, Thomas E},\n doi = {10.1115/OMAE2011-49262},\n booktitle = {Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE}\n}
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\n We computationally investigate the ability of a cycloidal turbine to cancel two-dimensional non-harmonic waves in deep water. A cycloidal turbine employs the same geometry as the well established Cycloidal or Voith-Schneider Propeller. It consists of a shaft and one or more hydrofoils that are attached eccentrically to the main shaft and can be independently adjusted in pitch angle as the cycloidal turbine rotates. We simulate the cycloidal turbine interaction with incoming waves by viewing the turbine as a wave generator superimposed with the incoming flow. The generated waves ideally are 180° out of phase and cancel the incoming wave downstream of the turbine. The upstream wave is very small as generation of single-sided waves is a characteristic of the cycloidal turbine as has been shown in prior work. The superposition of the incoming wave and generated wave is investigated in the far-field and we model the hydrofoil as a point vortex. This model has previously been used to successfully terminate regular deep water waves as well as intermediate depth water waves. We explore the ability of this model to cancel nonharmonic waves. Near complete cancellation is possible for a non-harmonic wave with components designed to match those generated by the cycloidal turbine for specified parameters. Cancellation of a specific wave component of a multi-component system is also shown. Also, step changes in the device operating parameters of circulation strength, rotation rate, and submergence depth are explored to give insight to the cycloidal turbine response characteristics and adaptability to changes in incoming waves. Based on these studies a linear, time-invarient (LTI) model is developed which captures the steady state wave frequency response. Such a model can be used for control development in future efforts to efficiently cancel more complex incoming waves. Copyright © 2011 by ASME.\n
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\n  \n 2010\n \n \n (1)\n \n \n
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\n \n\n \n \n \n \n \n Intermediate ocean wave termination using a cycloidal wave energy converter.\n \n \n \n\n\n \n Siegel, S., G.; Jeans, T.; and McLaughlin, T., E.\n\n\n \n\n\n\n In Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE, volume 3, pages 293-301, 2010. \n \n\n\n\n
\n\n\n\n \n\n \n \n doi\n  \n \n\n \n link\n  \n \n\n bibtex\n \n\n \n  \n \n abstract \n \n\n \n\n \n \n \n \n \n \n \n\n  \n \n \n\n\n\n
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@inproceedings{\n title = {Intermediate ocean wave termination using a cycloidal wave energy converter},\n type = {inproceedings},\n year = {2010},\n pages = {293-301},\n volume = {3},\n id = {e8cff3fe-0b60-34ca-9dde-3df83585b6fe},\n created = {2020-04-03T12:35:32.949Z},\n file_attached = {false},\n profile_id = {80f79df7-70c4-3a7b-8290-0309ce34e49b},\n group_id = {a8cd9ed8-fd6b-32bd-a7ad-27ef75b1faca},\n last_modified = {2020-04-03T12:38:43.476Z},\n read = {false},\n starred = {false},\n authored = {false},\n confirmed = {true},\n hidden = {false},\n private_publication = {false},\n abstract = {We investigate a lift based wave energy converter (WEC), namely, a cycloidal turbine, as a wave termination device. A cycloidal turbine employs the same geometry as the well established Cycloidal or Voith-Schneider Propeller. The interaction of intermediate water waves with the Cycloidal WEC is presented in this paper. The cycloidal WEC consists of a shaft and one or more hydrofoils that are attached eccentrically to the main shaft and can be adjusted in pitch angle as the Cycloidal WEC rotates. The main shaft is aligned parallel to the wave crests and fully submerged at a fixed depth. We show that the geometry of the Cycloidal WEC is suitable for wave termination of straight crested waves. Two-dimensional potential flow simulations are presented where the hydrofoils are modeled as point vortices. The operation of the Cycloidal WEC both as a wave generator as well as a wave energy converter interacting with a linear Airy wave is demonstrated. The influence that the design parameters radius and submergence depth on the performance of the WEC have is shown. For optimal parameter choices, we demonstrate inviscid energy conversion efficiencies of up to 95% of the incoming wave energy to shaft energy. This is achieved by using feedback control to synchronize the rotational rate and phase of the Cycloidal WEC to the incoming wave. While we show complete termination of the incoming wave, the remainder of the energy is lost to harmonic waves travelling in the upwave and downwave direction. Copyright © 2010 by ASME.},\n bibtype = {inproceedings},\n author = {Siegel, Stefan G. and Jeans, Tiger and McLaughlin, Thomas E},\n doi = {10.1115/OMAE2010-20030},\n booktitle = {Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE}\n}
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\n We investigate a lift based wave energy converter (WEC), namely, a cycloidal turbine, as a wave termination device. A cycloidal turbine employs the same geometry as the well established Cycloidal or Voith-Schneider Propeller. The interaction of intermediate water waves with the Cycloidal WEC is presented in this paper. The cycloidal WEC consists of a shaft and one or more hydrofoils that are attached eccentrically to the main shaft and can be adjusted in pitch angle as the Cycloidal WEC rotates. The main shaft is aligned parallel to the wave crests and fully submerged at a fixed depth. We show that the geometry of the Cycloidal WEC is suitable for wave termination of straight crested waves. Two-dimensional potential flow simulations are presented where the hydrofoils are modeled as point vortices. The operation of the Cycloidal WEC both as a wave generator as well as a wave energy converter interacting with a linear Airy wave is demonstrated. The influence that the design parameters radius and submergence depth on the performance of the WEC have is shown. For optimal parameter choices, we demonstrate inviscid energy conversion efficiencies of up to 95% of the incoming wave energy to shaft energy. This is achieved by using feedback control to synchronize the rotational rate and phase of the Cycloidal WEC to the incoming wave. While we show complete termination of the incoming wave, the remainder of the energy is lost to harmonic waves travelling in the upwave and downwave direction. Copyright © 2010 by ASME.\n
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\n  \n 2008\n \n \n (1)\n \n \n
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\n \n\n \n \n \n \n \n Configurations and methods for wave energy extraction.\n \n \n \n\n\n \n Wegener, P.; and Berg, J.\n\n\n \n\n\n\n 2008.\n \n\n\n\n
\n\n\n\n \n\n \n\n \n link\n  \n \n\n bibtex\n \n\n \n  \n \n abstract \n \n\n \n\n \n \n \n \n \n \n \n\n  \n \n \n\n\n\n
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@misc{\n title = {Configurations and methods for wave energy extraction},\n type = {misc},\n year = {2008},\n pages = {8},\n revision = {US 2008/0238102 A1},\n id = {39907d18-0736-3026-956b-f69c1070ecc1},\n created = {2020-05-07T08:36:19.295Z},\n file_attached = {false},\n profile_id = {191d98fc-2728-3909-a066-d0f90f3eaa56},\n group_id = {a8cd9ed8-fd6b-32bd-a7ad-27ef75b1faca},\n last_modified = {2020-05-07T08:36:19.295Z},\n read = {false},\n starred = {false},\n authored = {false},\n confirmed = {true},\n hidden = {false},\n patent_application_number = {US 2008/0238102 A1},\n private_publication = {false},\n abstract = {A wave energy harvester (100A) includes an element (120A) that converts forward and/or backward of water in a wave (102A, B, C) passing the harvester (100A) into upward and/or downward movement to thereby increase the vertical ampli tude of the harvester (100A) relative to the sea floor (104A, B, C). In most preferred aspects, the element (120A) is a hydro foil that is coupled to the harvester (100A). Further preferred aspects include those in which part of, or the entire harvester (100A) has a neutral buoyancy, and where energy is extracted from the downwards movement of the neutrally buoyant part (100A) after a wave has lifted that part (110A).},\n bibtype = {misc},\n author = {Wegener, P and Berg, J}\n}
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\n A wave energy harvester (100A) includes an element (120A) that converts forward and/or backward of water in a wave (102A, B, C) passing the harvester (100A) into upward and/or downward movement to thereby increase the vertical ampli tude of the harvester (100A) relative to the sea floor (104A, B, C). In most preferred aspects, the element (120A) is a hydro foil that is coupled to the harvester (100A). Further preferred aspects include those in which part of, or the entire harvester (100A) has a neutral buoyancy, and where energy is extracted from the downwards movement of the neutrally buoyant part (100A) after a wave has lifted that part (110A).\n
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\n  \n 1995\n \n \n (1)\n \n \n
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\n \n\n \n \n \n \n \n Predictions of the hydrodynamic performance of the wave rotor wave energy device.\n \n \n \n\n\n \n Chaplin, J., R.; and Retzler, C., H.\n\n\n \n\n\n\n Applied Ocean Research, 17(6): 343-347. 12 1995.\n \n\n\n\n
\n\n\n\n \n\n \n \n doi\n  \n \n\n \n link\n  \n \n\n bibtex\n \n\n \n  \n \n abstract \n \n\n \n\n \n \n \n \n \n \n \n\n  \n \n \n \n \n \n \n \n \n \n \n \n \n\n\n\n
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@article{\n title = {Predictions of the hydrodynamic performance of the wave rotor wave energy device},\n type = {article},\n year = {1995},\n keywords = {Wave energy,free surface,horizontal cylinder,vortex,wave generation},\n pages = {343-347},\n volume = {17},\n month = {12},\n publisher = {Elsevier},\n day = {1},\n id = {6ebbaba1-e107-3a3b-8c9d-97ddc1f88eb7},\n created = {2020-04-08T15:58:05.276Z},\n accessed = {2020-04-08},\n file_attached = {false},\n profile_id = {80f79df7-70c4-3a7b-8290-0309ce34e49b},\n group_id = {a8cd9ed8-fd6b-32bd-a7ad-27ef75b1faca},\n last_modified = {2020-04-08T15:58:05.276Z},\n read = {false},\n starred = {false},\n authored = {false},\n confirmed = {false},\n hidden = {false},\n private_publication = {false},\n abstract = {This paper provides a linear solution for the Wave Rotor, a wave energy device that comprises two parallel counter rotating cylinders in orbital motion. Theoretical results are obtained for the radiated waves generated by the device, and for its efficiency. Comparisons with earlier measurements of radiated waves show very promising agreement. © 1996.},\n bibtype = {article},\n author = {Chaplin, J. R. and Retzler, C. H.},\n doi = {10.1016/S0141-1187(96)00017-X},\n journal = {Applied Ocean Research},\n number = {6}\n}
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\n This paper provides a linear solution for the Wave Rotor, a wave energy device that comprises two parallel counter rotating cylinders in orbital motion. Theoretical results are obtained for the radiated waves generated by the device, and for its efficiency. Comparisons with earlier measurements of radiated waves show very promising agreement. © 1996.\n
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\n  \n 1990\n \n \n (1)\n \n \n
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\n \n\n \n \n \n \n \n A device to extract energy from water waves.\n \n \n \n\n\n \n Hermans, A., J.; Van Sabben, E.; and Pinkster, J., A.\n\n\n \n\n\n\n Applied Ocean Research, 12(4): 175-179. 1990.\n \n\n\n\n
\n\n\n\n \n\n \n \n doi\n  \n \n\n \n link\n  \n \n\n bibtex\n \n\n \n\n \n\n \n \n \n \n \n \n \n\n  \n \n \n\n\n\n
\n
@article{\n title = {A device to extract energy from water waves},\n type = {article},\n year = {1990},\n pages = {175-179},\n volume = {12},\n id = {08f57247-ff1b-31a4-b08d-b754552bd5f6},\n created = {2020-04-08T16:02:39.638Z},\n accessed = {2020-04-08},\n file_attached = {false},\n profile_id = {80f79df7-70c4-3a7b-8290-0309ce34e49b},\n group_id = {a8cd9ed8-fd6b-32bd-a7ad-27ef75b1faca},\n last_modified = {2020-04-08T16:02:39.638Z},\n read = {false},\n starred = {false},\n authored = {false},\n confirmed = {false},\n hidden = {false},\n private_publication = {false},\n bibtype = {article},\n author = {Hermans, A. J. and Van Sabben, E. and Pinkster, J. A.},\n doi = {10.1016/S0141-1187(05)80024-0},\n journal = {Applied Ocean Research},\n number = {4}\n}
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