The integrated system composed of wave energy converters and floating wind turbines offers substantial potential for reducing the levelized cost of energy(LCOE) by sharing the infrastructure, mooring system, substatio...The integrated system composed of wave energy converters and floating wind turbines offers substantial potential for reducing the levelized cost of energy(LCOE) by sharing the infrastructure, mooring system, substations and cables.This paper proposes an integrated system consisting of a semi-submersible wind turbine platform and three Wave Star flap-type wave energy converters. The coupled motion model of the integrated system is established and validated on the basis of viscously corrected potential flow theory. This study investigates the influence of two key parameters,the arm length and hinge points of flap-type wave energy converters, on system performance. The results reveal that variations in the arm length of flap-type wave energy converters(WECs) are the primary determinants of the integrated system's dynamic characteristics, whereas changes in hinge points predominantly affect device power generation.Additionally, incorporating WECs reduces the pitch and heave motions of the platform within a specific wave frequency range, thereby enhancing the energy output of the integrated system at the operational sea site. The performance of this hybrid system at a selected sea site is further assessed via the proposed aero-hydroservo coupling simulations.展开更多
Considering the dependent relationship among wave height,wind speed,and current velocity,we construct novel trivariate joint probability distributions via Archimedean copula functions.Total 30-year data of wave height...Considering the dependent relationship among wave height,wind speed,and current velocity,we construct novel trivariate joint probability distributions via Archimedean copula functions.Total 30-year data of wave height,wind speed,and current velocity in the Bohai Sea are hindcast and sampled for case study.Four kinds of distributions,namely,Gumbel distribution,lognormal distribution,Weibull distribution,and Pearson Type III distribution,are candidate models for marginal distributions of wave height,wind speed,and current velocity.The Pearson Type III distribution is selected as the optimal model.Bivariate and trivariate probability distributions of these environmental conditions are established based on four bivariate and trivariate Archimedean copulas,namely,Clayton,Frank,Gumbel-Hougaard,and Ali-Mikhail-Haq copulas.These joint probability models can maximize marginal information and the dependence among the three variables.The design return values of these three variables can be obtained by three methods:univariate probability,conditional probability,and joint probability.The joint return periods of different load combinations are estimated by the proposed models.Platform responses(including base shear,overturning moment,and deck displacement) are further calculated.For the same return period,the design values of wave height,wind speed,and current velocity obtained by the conditional and joint probability models are much smaller than those by univariate probability.Considering the dependence among variables,the multivariate probability distributions provide close design parameters to actual sea state for ocean platform design.展开更多
This paper quantitatively studies the transient dynamic response of a semi-submersible production platform with the loss of one or several positioning mooring lines.A semi-submersible platform,production risers,and po...This paper quantitatively studies the transient dynamic response of a semi-submersible production platform with the loss of one or several positioning mooring lines.A semi-submersible platform,production risers,and positioning mooring lines are all included in the numerical simulation.Increased motion of the semi-submersible platform,tension variation of the remaining mooring lines/risers and the risk of mooring line or riser clashing are all investigated through fully coupled time-domain analysis.Combined environmental loads are selected from irregular waves and the steady current varying from very rough to extreme sea conditions.Three dimension radiation/diffraction theories and Morison’s equation are applied to calculate first-order wave force and second-order mean drift force of floating semi-submersible platform.Nonlinear time-domain finite element methods are employed to analyze the behavior of mooring lines and risers.Results show that the failure of mooring lines seriously reduce the platform’s stability performance.The tension of the rest lines is also increased accordingly.Remaining lines which are closer to the failed lines will have larger tension increase to compensate.Line-Line distance provides practical information for the risk of clashing investigation.展开更多
A dynamic response analysis of tension leg platform (TLP) to deterministic first order wave forces is presented, considering coupling between various degrees of freedom surge, sway, heave, pitch, roll and yaw. The ana...A dynamic response analysis of tension leg platform (TLP) to deterministic first order wave forces is presented, considering coupling between various degrees of freedom surge, sway, heave, pitch, roll and yaw. The analysis duly considers nonlinearities produced due to changes in cable-tension and due to nonlinear hydro-dynamic drag forces. The wave forces on the elements of the pontoon structure are calculated using Airy's wave theory and Morison's equation. The nonlinear equation of motion is solved in the time domain by Newmark's β-method. With the help of proposed analysis, some example problems are solved in order to investigate the effects of different important factors that influence the response of TLP.展开更多
基金financially supported by the National Natural Science Foundation of China National Outstanding Youth Science Fund Project (Grant No. 52222109)the National Natural Science Foundation of China (Grant No. 52201322)+1 种基金Guangdong Basic and Applied Basic Research Foundation (Grant Nos. 2024A1515240006, 2022B1515020036 and 2023A1515012144)the Project of State Key Laboratory of Subtropical Building and Urban Science (Grant No. 2023ZB14)。
文摘The integrated system composed of wave energy converters and floating wind turbines offers substantial potential for reducing the levelized cost of energy(LCOE) by sharing the infrastructure, mooring system, substations and cables.This paper proposes an integrated system consisting of a semi-submersible wind turbine platform and three Wave Star flap-type wave energy converters. The coupled motion model of the integrated system is established and validated on the basis of viscously corrected potential flow theory. This study investigates the influence of two key parameters,the arm length and hinge points of flap-type wave energy converters, on system performance. The results reveal that variations in the arm length of flap-type wave energy converters(WECs) are the primary determinants of the integrated system's dynamic characteristics, whereas changes in hinge points predominantly affect device power generation.Additionally, incorporating WECs reduces the pitch and heave motions of the platform within a specific wave frequency range, thereby enhancing the energy output of the integrated system at the operational sea site. The performance of this hybrid system at a selected sea site is further assessed via the proposed aero-hydroservo coupling simulations.
基金partially supported by the National Natural Science Foundation of China(No.51479183)the National Key Research and Development Program,China(Nos.2016YFC0302301 and 2016YFC0803401)the Fundamental Research Funds for the Central University(No.201564003)
文摘Considering the dependent relationship among wave height,wind speed,and current velocity,we construct novel trivariate joint probability distributions via Archimedean copula functions.Total 30-year data of wave height,wind speed,and current velocity in the Bohai Sea are hindcast and sampled for case study.Four kinds of distributions,namely,Gumbel distribution,lognormal distribution,Weibull distribution,and Pearson Type III distribution,are candidate models for marginal distributions of wave height,wind speed,and current velocity.The Pearson Type III distribution is selected as the optimal model.Bivariate and trivariate probability distributions of these environmental conditions are established based on four bivariate and trivariate Archimedean copulas,namely,Clayton,Frank,Gumbel-Hougaard,and Ali-Mikhail-Haq copulas.These joint probability models can maximize marginal information and the dependence among the three variables.The design return values of these three variables can be obtained by three methods:univariate probability,conditional probability,and joint probability.The joint return periods of different load combinations are estimated by the proposed models.Platform responses(including base shear,overturning moment,and deck displacement) are further calculated.For the same return period,the design values of wave height,wind speed,and current velocity obtained by the conditional and joint probability models are much smaller than those by univariate probability.Considering the dependence among variables,the multivariate probability distributions provide close design parameters to actual sea state for ocean platform design.
基金supported by the Fundamental Research Funds for the Central Universities,Dalian Maritime University,China(Grant Nos.3132019306 and 3132020116).
文摘This paper quantitatively studies the transient dynamic response of a semi-submersible production platform with the loss of one or several positioning mooring lines.A semi-submersible platform,production risers,and positioning mooring lines are all included in the numerical simulation.Increased motion of the semi-submersible platform,tension variation of the remaining mooring lines/risers and the risk of mooring line or riser clashing are all investigated through fully coupled time-domain analysis.Combined environmental loads are selected from irregular waves and the steady current varying from very rough to extreme sea conditions.Three dimension radiation/diffraction theories and Morison’s equation are applied to calculate first-order wave force and second-order mean drift force of floating semi-submersible platform.Nonlinear time-domain finite element methods are employed to analyze the behavior of mooring lines and risers.Results show that the failure of mooring lines seriously reduce the platform’s stability performance.The tension of the rest lines is also increased accordingly.Remaining lines which are closer to the failed lines will have larger tension increase to compensate.Line-Line distance provides practical information for the risk of clashing investigation.
文摘A dynamic response analysis of tension leg platform (TLP) to deterministic first order wave forces is presented, considering coupling between various degrees of freedom surge, sway, heave, pitch, roll and yaw. The analysis duly considers nonlinearities produced due to changes in cable-tension and due to nonlinear hydro-dynamic drag forces. The wave forces on the elements of the pontoon structure are calculated using Airy's wave theory and Morison's equation. The nonlinear equation of motion is solved in the time domain by Newmark's β-method. With the help of proposed analysis, some example problems are solved in order to investigate the effects of different important factors that influence the response of TLP.
