Research

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23 pages, 5513 KiB

Open AccessArticle

Generation of Synthetic CPTs with Access to Limited Geotechnical Data for Offshore Sites

by Gohar Shoukat, Guillaume Michel, Mark Coughlan, Abdollah Malekjafarian, Indrasenan Thusyanthan, Cian Desmond and Vikram Pakrashi

Energies 2023, 16(9), 3817; https://doi.org/10.3390/en16093817 - 28 Apr 2023

Viewed by 1667

Abstract

The initial design phase for offshore wind farms does not require complete geotechnical mapping and individual cone penetration testing (CPT) for each expected turbine location. Instead, background information from open source studies and previous historic records for geology and seismic data are typically [...] Read more.

The initial design phase for offshore wind farms does not require complete geotechnical mapping and individual cone penetration testing (CPT) for each expected turbine location. Instead, background information from open source studies and previous historic records for geology and seismic data are typically used at this early stage to develop a preliminary ground model. This study focuses specifically on the interpolation and extrapolation of cone penetration test (CPT) data. A detailed methodology is presented for the process of using a limited number of CPTs to characterise the geotechnical behavior of an offshore site using artificial neural networks. In the presented study, the optimised neural network achieved a predictive error of

0.067

. Accuracy is greatest at depths of less than 10

m

. The pitfalls of using machine learning for geospatial interpolation are explained and discussed. Full article

(This article belongs to the Special Issue Numerical Analysis, Field Testing and Experimental Assessment of Offshore Wind Turbines 2023)

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22 pages, 3399 KiB

Open AccessFeature PaperArticle

Enabling Floating Offshore VAWT Design by Coupling OWENS and OpenFAST

by Michael C. Devin, Nicole R. Mendoza, Andrew Platt, Kevin Moore, Jason Jonkman and Brandon L. Ennis

Energies 2023, 16(5), 2462; https://doi.org/10.3390/en16052462 - 04 Mar 2023

Cited by 1 | Viewed by 2085

Abstract

Vertical-axis wind turbines (VAWTs) have a long history, with a wide variety of turbine archetypes that have been designed and tested since the 1970s. While few utility-scale VAWTs currently exist, the placement of the generator near the turbine base could make VAWTs advantageous [...] Read more.

Vertical-axis wind turbines (VAWTs) have a long history, with a wide variety of turbine archetypes that have been designed and tested since the 1970s. While few utility-scale VAWTs currently exist, the placement of the generator near the turbine base could make VAWTs advantageous over tradition horizontal-axis wind turbines for floating offshore wind applications via reduced platform costs and improved scaling potential. However, there are currently few numerical design and analysis tools available for VAWTs. One existing engineering toolset for aero-hydro-servo-elastic simulation of VAWTs is the Offshore Wind ENergy Simulator (OWENS), but its current modeling capability for floating systems is non-standard and not ideal. This article describes how OWENS has been coupled to several OpenFAST modules to update and improve modeling of floating offshore VAWTs and discusses the verification of these new capabilities and features. The results of the coupled OWENS verification test agree well with a parallel OpenFAST simulation, validating the new modeling and simulation capabilities in OWENS for floating VAWT applications. These developments will enable the design and optimization of floating offshore VAWTs in the future. Full article

(This article belongs to the Special Issue Numerical Analysis, Field Testing and Experimental Assessment of Offshore Wind Turbines 2023)

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13 pages, 3115 KiB

Open AccessEditor’s ChoiceArticle

Risk Assessment of Offshore Wind Turbines Suction Bucket Foundation Subject to Multi-Hazard Events

by Duc-Vu Ngo, Young-Jin Kim and Dong-Hyawn Kim

Energies 2023, 16(5), 2184; https://doi.org/10.3390/en16052184 - 24 Feb 2023

Cited by 4 | Viewed by 1987

Abstract

For the offshore wind turbines (OWTs) located in a seismically active region, the occurrence of earthquakes combined with scour is a highly possible multi-hazard event. This study developed an alternative fragility analysis framework to assess the seismic performance of suction bucket-supported OWTs under [...] Read more.

For the offshore wind turbines (OWTs) located in a seismically active region, the occurrence of earthquakes combined with scour is a highly possible multi-hazard event. This study developed an alternative fragility analysis framework to assess the seismic performance of suction bucket-supported OWTs under the action of scour. First, the probabilistic approach was applied to calculate the occurrence probability of scour depth (SD) and earthquake events. Then, the possible combinations of these two events were considered in the analysis model to establish the fragility surface of the suction bucket foundation. Finally, by integrating the product of scour and earthquake hazard, as well as fragility curves, the suction bucket foundation failure probability was obtained. The developed framework provides a reliable approach to risk assessment for OWT-supporting structures in extreme event situations and can be applied to other complex natural hazards. Full article

(This article belongs to the Special Issue Numerical Analysis, Field Testing and Experimental Assessment of Offshore Wind Turbines 2023)

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15 pages, 5616 KiB

Open AccessArticle

Advanced Methods for Wind Turbine Performance Analysis Based on SCADA Data and CFD Simulations

by Francesco Castellani, Ravi Pandit, Francesco Natili, Francesca Belcastro and Davide Astolfi

Energies 2023, 16(3), 1081; https://doi.org/10.3390/en16031081 - 18 Jan 2023

Cited by 1 | Viewed by 1500

Abstract

Deep comprehension of wind farm performance is a complicated task due to the multivariate dependence of wind turbine power on environmental variables and working parameters and to the intrinsic limitations in the quality of SCADA-collected measurements. Given this, the objective of this study [...] Read more.

Deep comprehension of wind farm performance is a complicated task due to the multivariate dependence of wind turbine power on environmental variables and working parameters and to the intrinsic limitations in the quality of SCADA-collected measurements. Given this, the objective of this study is to propose an integrated approach based on SCADA data and Computational Fluid Dynamics simulations, which is aimed at wind farm performance analysis. The selected test case is a wind farm situated in southern Italy, where two wind turbines had an apparent underperformance. The concept of a space–time comparison at the wind farm level is leveraged by analyzing the operation curves of the wind turbines and by comparing the simulated average wind field against the measured one, where each wind turbine is treated like a virtual meteorological mast. The employed formulation for the CFD simulations is Reynolds-Average Navier–Stokes (RANS). In this work, it is shown that, based on the above approach, it has been possible to identify an anemometer bias at a wind turbine, which has subsequently been fixed. The results of this work affirm that a deep comprehension of wind farm performance requires a non-trivial space–time comparison, of which CFD simulations can be a fundamental part. Full article

(This article belongs to the Special Issue Numerical Analysis, Field Testing and Experimental Assessment of Offshore Wind Turbines 2023)

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25 pages, 5365 KiB

Open AccessEditor’s ChoiceArticle

Verification and Validation of Model-Scale Turbine Performance and Control Strategies for the IEA Wind 15 MW Reference Wind Turbine

by Nicole Mendoza, Amy Robertson, Alan Wright, Jason Jonkman, Lu Wang, Roger Bergua, Tri Ngo, Tuhin Das, Mohammad Odeh, Kazi Mohsin, Francesc Fabregas Flavia, Benjamin Child, Galih Bangga, Matthew Fowler, Andrew Goupee, Richard Kimball, Eben Lenfest and Anthony Viselli

Energies 2022, 15(20), 7649; https://doi.org/10.3390/en15207649 - 17 Oct 2022

Cited by 16 | Viewed by 2771

Abstract

To enable the fast growth of the floating offshore wind industry, simulation models must be validated with experimental data. Floating wind model-scale experiments in wind–wave facilities have been performed over the last two decades with varying levels of fidelity and limitations. However, the [...] Read more.

To enable the fast growth of the floating offshore wind industry, simulation models must be validated with experimental data. Floating wind model-scale experiments in wind–wave facilities have been performed over the last two decades with varying levels of fidelity and limitations. However, the turbine controls in these experiments have considered only limited control strategies and implementations. To allow for control co-design, this research focuses on implementing and experimentally validating more advanced turbine control actions and strategies in a wind–wave basin for a 1:70-scale model of the International Energy Agency’s wind 15 MW reference wind turbine. The control strategies analyzed include torque control, collective pitch control, and transition region control (setpoint smoothing). Our experimental and numerical results include the effects of varying rotor speeds, blade pitches, and wind environments on the turbine thrust and torque. Numerical models from three different software tools are presented and compared to the experimental results. Their ability to effectively represent the aero-dynamic response of the wind turbine to the control actions is successfully validated. Finally, turbine controller tuning parameters based on the derivatives of thrust and torque are derived to allow for improved offshore wind turbine dynamics and to validate the ability of modeling tools to model the dynamics of floating offshore wind turbines with control co-design. Full article

(This article belongs to the Special Issue Numerical Analysis, Field Testing and Experimental Assessment of Offshore Wind Turbines 2023)

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22 pages, 4358 KiB

Open AccessArticle

Effect of Heave Plates on the Wave Motion of a Flexible Multicolumn FOWT

by Taisuke Takata, Mayuko Takaoka, Hidetaka Houtani, Kentaro Hara, Sho Oh, Edgard B. Malta, Kazuhiro Iijima, Hideyuki Suzuki and Rodolfo T. Gonçalves

Energies 2022, 15(20), 7605; https://doi.org/10.3390/en15207605 - 14 Oct 2022

Cited by 5 | Viewed by 1374

Abstract

Three models with different footing types were used to clarify the effect of heave plates on the hydrodynamic behavior of the elastic response of a flexible multicolumn floating offshore wind turbine (FOWT). The models were tested under regular waves, whose added mass, damping, [...] Read more.

Three models with different footing types were used to clarify the effect of heave plates on the hydrodynamic behavior of the elastic response of a flexible multicolumn floating offshore wind turbine (FOWT). The models were tested under regular waves, whose added mass, damping, and motion response results were compared with numerical simulations by NK-UTWind and WAMIT codes. As a whole, the attachment of heave plates was responsible for increasing the added mass and damping levels, consequently modifying the RAO of the models. Regarding the response in a sea condition, a decrease of 33% and 66% of the significant motion height (heave and pitch) was observed. Thus, the heave plate can be a good feature for the future design of FOWT. Full article

(This article belongs to the Special Issue Numerical Analysis, Field Testing and Experimental Assessment of Offshore Wind Turbines 2023)

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16 pages, 1283 KiB

Open AccessArticle

Organization and Reliability Testing of a Wind Farm Device in Its Operational Process

by Stanisław Duer, Krzysztof Rokosz, Dariusz Bernatowicz, Arkadiusz Ostrowski, Marek Woźniak, Konrad Zajkowski and Atif Iqbal

Energies 2022, 15(17), 6255; https://doi.org/10.3390/en15176255 - 27 Aug 2022

Cited by 2 | Viewed by 964

Abstract

This article deals with the importance of simulation studies for the reliability of wind farm (WF) equipment during the operation process. Improvements, upgrades, and the introduction of new solutions that change the reliability, quality, and conditions of use and operation of wind farm [...] Read more.

This article deals with the importance of simulation studies for the reliability of wind farm (WF) equipment during the operation process. Improvements, upgrades, and the introduction of new solutions that change the reliability, quality, and conditions of use and operation of wind farm equipment present a research problem during study. Based on this research, it is possible to continuously evaluate the reliability of WF equipment. The topic of reliability testing of complex technical facilities is constantly being developed in the literature. The article assumes that the operation of wind farm equipment is described and modeled based on Markov processes. This assumption justified the use of Kolmogorov–Chapman equations to describe the developed research model. Based on these equations, an analytical model of the wind farm operation process was created and described. As a result of the simulation analysis, the reliability of the wind farm was determined in the form of a probability function (R0(t)) for the WPPs system. Full article

(This article belongs to the Special Issue Numerical Analysis, Field Testing and Experimental Assessment of Offshore Wind Turbines 2023)

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Review

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27 pages, 13631 KiB

Open AccessFeature PaperReview

A Review of Recent Aerodynamic Power Extraction Challenges in Coordinated Pitch, Yaw, and Torque Control of Large-Scale Wind Turbine Systems

by Kumarasamy Palanimuthu, Ganesh Mayilsamy, Ameerkhan Abdul Basheer, Seong-Ryong Lee, Dongran Song and Young Hoon Joo

Energies 2022, 15(21), 8161; https://doi.org/10.3390/en15218161 - 01 Nov 2022

Cited by 7 | Viewed by 1744

Abstract

As the impacts of environmental change become more severe, reliable and sustainable power generation and efficient aerodynamic power collection of onshore and offshore wind turbine systems present some of the associated key issues to address. Therefore, this review article aims to present current [...] Read more.

As the impacts of environmental change become more severe, reliable and sustainable power generation and efficient aerodynamic power collection of onshore and offshore wind turbine systems present some of the associated key issues to address. Therefore, this review article aims to present current advances and challenges in the aerodynamic power extraction of wind turbines, associated supporting technologies in pitch, yaw, and torque control systems, and their advantages and implications in the renewable energy industry under environmental challenges. To do this, first, mathematical modeling of the environmental characteristics of the wind turbine system is presented. Next, the latest technological advances consider the environmental challenges presented in the literature, and merits and drawbacks are discussed. In addition, pioneering research works and state-of-the-art methodologies are categorized and evaluated according to pitch, yaw, and torque control objectives. Finally, simulation results are presented to demonstrate the impact of environmental issues, improvement claims, findings, and trade-offs of techniques found in the literature on super-large wind turbine systems. Thus, this study is expected to lay the groundwork for future intensive efforts to better understand the performance of large-scale wind turbine systems in addressing environmental issues. Full article

(This article belongs to the Special Issue Numerical Analysis, Field Testing and Experimental Assessment of Offshore Wind Turbines 2023)

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