A. Fontanella, F. Taruffi, S. Muggiasca, M. Belloli
This paper discusses the methodology introduced by the authors to design a large-scale wind turbine model starting from the DTU 10MW RWT. The wind turbine will be coupled with the model of a multi-purpose floating structure, designed within the EU H2020 Blue Growth Farm project, and it will be deployed at the Natural Ocean Engineering Laboratory (NOEL). In this paper the different strategies used to design the wind turbine model rotor, tower and nacelle are discussed, focusing on how it has been possible to reproduce the full-scale system aero-elastic response while ensuring the same functionalities of a real wind turbine.
{"title":"Design Methodology for a Floating Offshore Wind Turbine Large-Scale Outdoor Prototype","authors":"A. Fontanella, F. Taruffi, S. Muggiasca, M. Belloli","doi":"10.1115/omae2019-95979","DOIUrl":"https://doi.org/10.1115/omae2019-95979","url":null,"abstract":"\u0000 This paper discusses the methodology introduced by the authors to design a large-scale wind turbine model starting from the DTU 10MW RWT. The wind turbine will be coupled with the model of a multi-purpose floating structure, designed within the EU H2020 Blue Growth Farm project, and it will be deployed at the Natural Ocean Engineering Laboratory (NOEL). In this paper the different strategies used to design the wind turbine model rotor, tower and nacelle are discussed, focusing on how it has been possible to reproduce the full-scale system aero-elastic response while ensuring the same functionalities of a real wind turbine.","PeriodicalId":306681,"journal":{"name":"Volume 10: Ocean Renewable Energy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126044689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study is concerned with motion analysis and hydroelastic response of a floating offshore wind turbine to wave loads. The novel floating structure, made of prestressed concrete, is designed to support multiple wind turbines, and it rotates according to the environmental loads to face the incoming wind. The floating structure is attached to a mooring line that allows the rotation of the structure in response to the environmental loads. The floating structure is an equilateral triangular platform. The wind turbines are located at the vertices. Due to the dimensional characteristics of the structure, elasticity of the floating platform plays an important role in its dynamics. While the dynamic response of the structure is driven by both aerodynamic and hydrodynamic loads, this study focuses on the motion and elastic response of the novel floating structure to the hydrodynamic loads only. The three dimensional hydrodynamic loads on the floating structure are obtained by use of the constant panel approach of the Green function method, subject to linear mooring loads. A finite element analysis is carried out for the calculation of the elastic response of the structure. Computations of the integrated linear structure-fluid-structure interaction problem are performed in frequency domain using HYDRAN, a computer program written for the linear dynamic analysis of rigid and flexible bodies. Results presented here include the response amplitude operators of both the rigid and flexible bodies to incoming waves of various frequencies and directions. Also presented are the wave-induced stresses on the floating body, and the elastic deformations.
{"title":"On Motion and Hydroelastic Analysis of a Floating Offshore Wind Turbine","authors":"A. Lamei, M. Hayatdavoodi, C. Wong, B. Tang","doi":"10.1115/omae2019-96034","DOIUrl":"https://doi.org/10.1115/omae2019-96034","url":null,"abstract":"\u0000 This study is concerned with motion analysis and hydroelastic response of a floating offshore wind turbine to wave loads. The novel floating structure, made of prestressed concrete, is designed to support multiple wind turbines, and it rotates according to the environmental loads to face the incoming wind. The floating structure is attached to a mooring line that allows the rotation of the structure in response to the environmental loads. The floating structure is an equilateral triangular platform. The wind turbines are located at the vertices. Due to the dimensional characteristics of the structure, elasticity of the floating platform plays an important role in its dynamics. While the dynamic response of the structure is driven by both aerodynamic and hydrodynamic loads, this study focuses on the motion and elastic response of the novel floating structure to the hydrodynamic loads only. The three dimensional hydrodynamic loads on the floating structure are obtained by use of the constant panel approach of the Green function method, subject to linear mooring loads. A finite element analysis is carried out for the calculation of the elastic response of the structure. Computations of the integrated linear structure-fluid-structure interaction problem are performed in frequency domain using HYDRAN, a computer program written for the linear dynamic analysis of rigid and flexible bodies. Results presented here include the response amplitude operators of both the rigid and flexible bodies to incoming waves of various frequencies and directions. Also presented are the wave-induced stresses on the floating body, and the elastic deformations.","PeriodicalId":306681,"journal":{"name":"Volume 10: Ocean Renewable Energy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114774175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Second-order components of wave loads acting on the floating foundation for wind turbines may induce severe resonance and lead to fatigue damage at natural frequencies of structures. In this study, the INNWIND.EU Triple-Spar and the DTU 10 MW Reference Wind Turbine were simulated by utilizing software FAST to obtain the second-order responses of the floating wind turbine under selected steady winds with collinear random waves. Low-frequency responses at surge and pitch natural frequencies dominated the response spectra, which were underestimated by the first-order numerical model. A response peak appeared in tower-top motion spectrum in vicinity of the first-order fore-aft vibration frequency of the tower when the sum-frequency wave effects were considered. The second-order high-frequency responses arose when the full QTF was utilized, compared to results with Newman approximation. Different operating conditions with varying wind speeds, wave periods, significant wave heights and wave directions were selected to conduct the sensitivity study of the second-order responses.
{"title":"Second-Order Responses of a 10 MW Floating Wind Turbine, Considering the Full QTF","authors":"Qun Cao, Longfei Xiao, Xiaoxian Guo, Mingyue Liu","doi":"10.1115/omae2019-95661","DOIUrl":"https://doi.org/10.1115/omae2019-95661","url":null,"abstract":"\u0000 Second-order components of wave loads acting on the floating foundation for wind turbines may induce severe resonance and lead to fatigue damage at natural frequencies of structures. In this study, the INNWIND.EU Triple-Spar and the DTU 10 MW Reference Wind Turbine were simulated by utilizing software FAST to obtain the second-order responses of the floating wind turbine under selected steady winds with collinear random waves. Low-frequency responses at surge and pitch natural frequencies dominated the response spectra, which were underestimated by the first-order numerical model. A response peak appeared in tower-top motion spectrum in vicinity of the first-order fore-aft vibration frequency of the tower when the sum-frequency wave effects were considered. The second-order high-frequency responses arose when the full QTF was utilized, compared to results with Newman approximation. Different operating conditions with varying wind speeds, wave periods, significant wave heights and wave directions were selected to conduct the sensitivity study of the second-order responses.","PeriodicalId":306681,"journal":{"name":"Volume 10: Ocean Renewable Energy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116735906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A wave energy converter (WEC) must be designed to survive the extreme sea states that it will be subject to throughout its lifetime. Although there are many analysis methods and codes available to accomplish this, there are currently several engineering challenges to WEC survival design. Foremost, the computational design approach will typically involve a trade-off between accuracy and computational efficiency. Additionally, most computational fluid dynamics (CFD) codes are not ideally suited to modeling extreme events for WECs with multibody dynamics, power-take-off systems, and mooring systems. Finally, although WEC design standards and CFD guidelines are emerging, with the current immaturity of the WEC industry, they are not yet well established. In this study, loads on a 1:35-scale, moored, multibody WEC are evaluated with CFD. The CFD results are compared with results obtained from a computationally efficient, midfidelity model based on linearized potential flow hydrodynamics. For these model verification comparisons, both operational and survival configurations are considered. The extreme load results obtained, using both codes, indicate that the survival configuration successfully sheds loads during extreme sea states. It is also found that WEC-Sim, when appropriately applied, can provide reasonable load results, at a fraction of the computational expense of CFD. However, for the more extreme sea states, and for higher-order effects not included in the WEC-Sim model, the linear-based results have significant errors in comparison to the CFD-based results, and should be used judiciously.
{"title":"Extreme Load Computational Fluid Dynamics Analysis and Verification for a Multibody Wave Energy Converter","authors":"J. V. Rij, Yi-Hsiang Yu, A. Mccall, R. Coe","doi":"10.1115/omae2019-96397","DOIUrl":"https://doi.org/10.1115/omae2019-96397","url":null,"abstract":"\u0000 A wave energy converter (WEC) must be designed to survive the extreme sea states that it will be subject to throughout its lifetime. Although there are many analysis methods and codes available to accomplish this, there are currently several engineering challenges to WEC survival design. Foremost, the computational design approach will typically involve a trade-off between accuracy and computational efficiency. Additionally, most computational fluid dynamics (CFD) codes are not ideally suited to modeling extreme events for WECs with multibody dynamics, power-take-off systems, and mooring systems. Finally, although WEC design standards and CFD guidelines are emerging, with the current immaturity of the WEC industry, they are not yet well established. In this study, loads on a 1:35-scale, moored, multibody WEC are evaluated with CFD. The CFD results are compared with results obtained from a computationally efficient, midfidelity model based on linearized potential flow hydrodynamics. For these model verification comparisons, both operational and survival configurations are considered. The extreme load results obtained, using both codes, indicate that the survival configuration successfully sheds loads during extreme sea states. It is also found that WEC-Sim, when appropriately applied, can provide reasonable load results, at a fraction of the computational expense of CFD. However, for the more extreme sea states, and for higher-order effects not included in the WEC-Sim model, the linear-based results have significant errors in comparison to the CFD-based results, and should be used judiciously.","PeriodicalId":306681,"journal":{"name":"Volume 10: Ocean Renewable Energy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125755051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
W. Shi, Lixian Zhang, Ning Dezhi, Zhiyu Jiang, C. Michailides, M. Karimirad
Currently, there is a great interest to globally develop offshore wind energy due to the greenhouse effect and energy crisis. Great efforts have been devoted to develop reliable floating offshore wind energy technology to exploit the wind energy resources in deep seas. This paper presents a comparative study of the dynamic response of three different semisubmersible floating wind turbine structures. All the three platforms support the same 5MW wind turbine. The platforms examined are: a V-shaped Semi, an OC4-DeepCwind Semi and a Braceless Semi at 200 m water depth. A dynamic analysis is carried out in order to calculate and compare the performance of these platforms. The comparison is made on the rigid body motions of the semisubmersible platform and tensions of the mooring lines. The presented comparison is based on statistical values and spectra of the time series of the examined response quantities. Coupling effects are more significant for the V-shaped Semi platform. The V-shaped Semi and the Braceless Semi show a more rational motion response under the investigated load cases. The results of this analysis may help to resolve the fundamental design tradeoffs between among different floating system concepts.
{"title":"A Comparative Study on the Dynamic Response of Three Semisubmersible Floating Offshore Wind Turbines","authors":"W. Shi, Lixian Zhang, Ning Dezhi, Zhiyu Jiang, C. Michailides, M. Karimirad","doi":"10.1115/OMAE2019-96221","DOIUrl":"https://doi.org/10.1115/OMAE2019-96221","url":null,"abstract":"\u0000 Currently, there is a great interest to globally develop offshore wind energy due to the greenhouse effect and energy crisis. Great efforts have been devoted to develop reliable floating offshore wind energy technology to exploit the wind energy resources in deep seas. This paper presents a comparative study of the dynamic response of three different semisubmersible floating wind turbine structures. All the three platforms support the same 5MW wind turbine. The platforms examined are: a V-shaped Semi, an OC4-DeepCwind Semi and a Braceless Semi at 200 m water depth. A dynamic analysis is carried out in order to calculate and compare the performance of these platforms. The comparison is made on the rigid body motions of the semisubmersible platform and tensions of the mooring lines. The presented comparison is based on statistical values and spectra of the time series of the examined response quantities. Coupling effects are more significant for the V-shaped Semi platform. The V-shaped Semi and the Braceless Semi show a more rational motion response under the investigated load cases. The results of this analysis may help to resolve the fundamental design tradeoffs between among different floating system concepts.","PeriodicalId":306681,"journal":{"name":"Volume 10: Ocean Renewable Energy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124377387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Stefek, D. Bain, Yi-Hsiang Yu, D. Jenne, Greg Stark
Reducing power fluctuations is essential for controlling the integration impacts of wave energy converter (WEC) plants in both distribution and transmission grids, and in stand-alone isolated power systems. This paper presents an analysis on the cost of and how a battery storage system can be used to further reduce the variation of power generated from the WEC due to the fluctuating nature of waves and its impact to the grid. The electrical power output from WEC-Sim simulations for the six sea states used in the Wave Energy Prize was analyzed to compute the peak power and power time history. The results were used to evaluate the battery storage capacity that is needed for a WEC system to provide reasonable power flow to the grid and estimate its cost based on the latest cost information for battery technologies published by the U.S. Energy Information Administration. Finally, a preliminary grid integration analysis was performed to demonstrate how WEC-generated power would contribute to a small island electricity system. As shown in the study, the instantaneous peak power is the primary cost driver for the battery storage and the power take-off system, and reducing the power fluctuations is essential for reducing the overall levelized cost of energy (LCOE). The power flow variation from WECs can be significantly reduced using battery storage without adding significant overall system costs, and the implementation of battery storage is essential for grid integration applications. There may also be additional opportunities to further investigate energy storage technologies that are specific to WEC applications to reduce these costs even further.
{"title":"Analysis on the Influence of an Energy Storage System and its Impact to the Grid for a Wave Energy Converter","authors":"J. Stefek, D. Bain, Yi-Hsiang Yu, D. Jenne, Greg Stark","doi":"10.1115/omae2019-96466","DOIUrl":"https://doi.org/10.1115/omae2019-96466","url":null,"abstract":"\u0000 Reducing power fluctuations is essential for controlling the integration impacts of wave energy converter (WEC) plants in both distribution and transmission grids, and in stand-alone isolated power systems. This paper presents an analysis on the cost of and how a battery storage system can be used to further reduce the variation of power generated from the WEC due to the fluctuating nature of waves and its impact to the grid. The electrical power output from WEC-Sim simulations for the six sea states used in the Wave Energy Prize was analyzed to compute the peak power and power time history. The results were used to evaluate the battery storage capacity that is needed for a WEC system to provide reasonable power flow to the grid and estimate its cost based on the latest cost information for battery technologies published by the U.S. Energy Information Administration. Finally, a preliminary grid integration analysis was performed to demonstrate how WEC-generated power would contribute to a small island electricity system. As shown in the study, the instantaneous peak power is the primary cost driver for the battery storage and the power take-off system, and reducing the power fluctuations is essential for reducing the overall levelized cost of energy (LCOE). The power flow variation from WECs can be significantly reduced using battery storage without adding significant overall system costs, and the implementation of battery storage is essential for grid integration applications. There may also be additional opportunities to further investigate energy storage technologies that are specific to WEC applications to reduce these costs even further.","PeriodicalId":306681,"journal":{"name":"Volume 10: Ocean Renewable Energy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122486424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The importance of properly modelling the effects of air compressibility in the selection of the optimal design parameters for an Oscillating Water Column wave energy converter is investigated. For this purpose, a wide dataset of capture width ratios, obtained from both experimental tests and Computational Fluid Dynamic simulations, is used to formulate an empirical model able to predict the performance of the device as a function of its basic design parameters (chamber width and draught, turbine damping) and of the wave conditions (wave period, wave height). A multiple non-linear regression approach is used to determine the model numerical coefficients. The data used to formulate the model include the effects of air compressibility. The impact of considering such effects on the selection of the optimal geometry of the device is evaluated and discussed by means of the model application for the optimization of a device to be installed in a site located in the Mediterranean Sea (in front of the coast of Tuscany, Italy).
{"title":"The Impact of Modelling Air Compressibility in the Selection of Optimal OWC Design Parameters in Site Specific Wave Conditions","authors":"I. Simonetti, L. Cappietti","doi":"10.1115/omae2019-96123","DOIUrl":"https://doi.org/10.1115/omae2019-96123","url":null,"abstract":"\u0000 The importance of properly modelling the effects of air compressibility in the selection of the optimal design parameters for an Oscillating Water Column wave energy converter is investigated. For this purpose, a wide dataset of capture width ratios, obtained from both experimental tests and Computational Fluid Dynamic simulations, is used to formulate an empirical model able to predict the performance of the device as a function of its basic design parameters (chamber width and draught, turbine damping) and of the wave conditions (wave period, wave height). A multiple non-linear regression approach is used to determine the model numerical coefficients. The data used to formulate the model include the effects of air compressibility. The impact of considering such effects on the selection of the optimal geometry of the device is evaluated and discussed by means of the model application for the optimization of a device to be installed in a site located in the Mediterranean Sea (in front of the coast of Tuscany, Italy).","PeriodicalId":306681,"journal":{"name":"Volume 10: Ocean Renewable Energy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122252018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Wuillaume, P. Ferrant, A. Babarit, Mattias Lynch
This paper presents a new mesh strategy for unsteady potential flow based solvers. It is based on the coupling between a panel cutting method used for the body mesh and an advance front method to generate the free surface mesh. The goal is to deal with complex geometries for time-domain simulations for marine operations. Firstly, the new mesh generation process is presented in details. Then, two validation tests are presented, using an academic geometry (vertical surface-piercing cylinder) and a complex geometry (FPSO).
{"title":"Development of a Panel Cutting Method Coupled With an Unsteady Potential Flow Model Based on the Weak-Scatterer Approximation","authors":"P. Wuillaume, P. Ferrant, A. Babarit, Mattias Lynch","doi":"10.1115/OMAE2019-96296","DOIUrl":"https://doi.org/10.1115/OMAE2019-96296","url":null,"abstract":"\u0000 This paper presents a new mesh strategy for unsteady potential flow based solvers. It is based on the coupling between a panel cutting method used for the body mesh and an advance front method to generate the free surface mesh. The goal is to deal with complex geometries for time-domain simulations for marine operations. Firstly, the new mesh generation process is presented in details. Then, two validation tests are presented, using an academic geometry (vertical surface-piercing cylinder) and a complex geometry (FPSO).","PeriodicalId":306681,"journal":{"name":"Volume 10: Ocean Renewable Energy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128544066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Schnabl, Túlio Marcondes Moreira, Dylan Wood, E. Kubatko, G. Houlsby, R. McAdam, T. Adcock
There are two approaches to extracting power from tides — either turbines are placed in areas of strong flows or turbines are placed in barrages enabling the two sides of the barrage to be closed off and a head to build up across the barrage. Both of these energy extraction approaches will have a significant back effect on the flow, and it is vital that this is correctly modelled in any numerical simulation of tidal hydrodynamics. This paper presents the inclusion of both tidal stream turbines and tidal barrages in the depth-averaged shallow water equation model DG-SWEM. We represent the head loss due to tidal stream turbines as a line discontinuity — thus we consider the turbines, and the energy lost in local wake-mixing behind the turbines, to be a sub-grid scale processes. Our code allows the inclusion of turbine power and thrust coefficients which are dependent on Froude number, turbine blockage, and velocity, but can be obtained from analytical or numerical models as well as experimental data. The barrage model modifies the existing culvert model within the code, replacing the original cross-barrier pipe equations. At the location of this boundary, velocities through sluice gates are calculated according to the orifice equation. For simulating the turbines, a Hill Chart for low head bulb turbines provided by Andritz Hydro is used. We demonstrate the implementations on both idealised geometries where it is straightforward to compare against other models and numerical simulations of real candidate sites for tidal energy in Malaysia and the Bristol Channel.
{"title":"Implementation of Tidal Stream Turbines and Tidal Barrage Structures in DG-SWEM","authors":"A. Schnabl, Túlio Marcondes Moreira, Dylan Wood, E. Kubatko, G. Houlsby, R. McAdam, T. Adcock","doi":"10.1115/omae2019-95767","DOIUrl":"https://doi.org/10.1115/omae2019-95767","url":null,"abstract":"\u0000 There are two approaches to extracting power from tides — either turbines are placed in areas of strong flows or turbines are placed in barrages enabling the two sides of the barrage to be closed off and a head to build up across the barrage. Both of these energy extraction approaches will have a significant back effect on the flow, and it is vital that this is correctly modelled in any numerical simulation of tidal hydrodynamics. This paper presents the inclusion of both tidal stream turbines and tidal barrages in the depth-averaged shallow water equation model DG-SWEM. We represent the head loss due to tidal stream turbines as a line discontinuity — thus we consider the turbines, and the energy lost in local wake-mixing behind the turbines, to be a sub-grid scale processes. Our code allows the inclusion of turbine power and thrust coefficients which are dependent on Froude number, turbine blockage, and velocity, but can be obtained from analytical or numerical models as well as experimental data. The barrage model modifies the existing culvert model within the code, replacing the original cross-barrier pipe equations. At the location of this boundary, velocities through sluice gates are calculated according to the orifice equation. For simulating the turbines, a Hill Chart for low head bulb turbines provided by Andritz Hydro is used.\u0000 We demonstrate the implementations on both idealised geometries where it is straightforward to compare against other models and numerical simulations of real candidate sites for tidal energy in Malaysia and the Bristol Channel.","PeriodicalId":306681,"journal":{"name":"Volume 10: Ocean Renewable Energy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117111939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Due to the complex nature of the loads on Offshore Wind Turbines (OWTs), accurate and optimized design of these structures require integrated simulation tools that can properly capture the various structural interactions governing the response. Considerable progress has been made in recent years on developing proper models for coupled aerodynamic and hydrodynamic loads together with advanced control systems for turbines. These efforts have resulted in a suite of aero-servo-hydro-elastic numerical simulation codes available to the industry. However, proper foundation models have been lagging behind in these tools despite availability of various advanced nonlinear models for foundations in general. This has led to uneconomical design of OWTs that have consistently failed to reproduce the measured natural frequencies and can negatively affect the design and structural performance of OWTs. This paper presents a library of recently developed foundation models based on the theory of plasticity together with their verification against large-scale field test data. These models are cast in the framework of macro-elements that represent the nonlinear response of the soil-foundation system due to arbitrary coupled loads at the seabed. The paper also presents results of the numerical simulations of the dynamic response of a monopile-based OWT in the North Sea using an aero-servo-hydro-elastic code and comparison with the data collected from one of the instrumented OWTs in the field. It is further presented how the characteristics of the measured dynamic response change with loading over a long period and the way the response characteristics relate to the basic features of the developed models.
{"title":"REDWIN Foundation Models for Integrated Dynamic Analyses of Offshore Wind Turbines","authors":"A. Page, K. Norén-Cosgriff, K. Skau, A. Kaynia","doi":"10.1115/omae2019-96168","DOIUrl":"https://doi.org/10.1115/omae2019-96168","url":null,"abstract":"\u0000 Due to the complex nature of the loads on Offshore Wind Turbines (OWTs), accurate and optimized design of these structures require integrated simulation tools that can properly capture the various structural interactions governing the response. Considerable progress has been made in recent years on developing proper models for coupled aerodynamic and hydrodynamic loads together with advanced control systems for turbines. These efforts have resulted in a suite of aero-servo-hydro-elastic numerical simulation codes available to the industry. However, proper foundation models have been lagging behind in these tools despite availability of various advanced nonlinear models for foundations in general. This has led to uneconomical design of OWTs that have consistently failed to reproduce the measured natural frequencies and can negatively affect the design and structural performance of OWTs.\u0000 This paper presents a library of recently developed foundation models based on the theory of plasticity together with their verification against large-scale field test data. These models are cast in the framework of macro-elements that represent the nonlinear response of the soil-foundation system due to arbitrary coupled loads at the seabed. The paper also presents results of the numerical simulations of the dynamic response of a monopile-based OWT in the North Sea using an aero-servo-hydro-elastic code and comparison with the data collected from one of the instrumented OWTs in the field. It is further presented how the characteristics of the measured dynamic response change with loading over a long period and the way the response characteristics relate to the basic features of the developed models.","PeriodicalId":306681,"journal":{"name":"Volume 10: Ocean Renewable Energy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124212214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：