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Hur, C. (author), Ferreira, C. (author), Schepers, J.G. (author)Horizontal axis wind turbines (HAWTs) experience yaw misalignments due to the phy sical limitations of yaw controllers and various novel active yaw controls. Moreover, the motion of floating offshore wind turbines (FOWTs) accelerates yaw misalignment. The blade element mo mentum (BEM) method is widely used due to its computational efficiency for...article 2022
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Koodly Ravishankara, A. (author), van der Weide, E. (author)Wind turbines are being installed in a wide array of offshore locations and are exposed to environmental condition during their operational lifetime. Rain, hailstones and accumulation of dust and insects can lead to turbine blades being eroded and contaminated. In this study, the effect of leading edge erosion on wind turbine blade performance...conference paper 2022
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Shankar Verma, A. (author), Jiang, Z. (author), Caboni, M. (author), Verhoef, J.P. (author), van der Mijle Meijer, H.J. (author), Castro, S.G.P. (author), Teuwen, J.J.E. (author)Rain-induced leading-edge erosion of wind turbine blades is associated with high repair and mainte nance costs. For efficient operation and maintenance, erosion models are required that provide estimates of blade coating lifetime at a real scale. In this study, a statistical rainfall model is established that de scribes probabilistic...article 2022
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Li, C. (author), Mogollón, J.M. (author), Tukker, A. (author), Dong, J. (author), von Terzi, D. (author), Zhang, C. (author), Steubing, B. (author)Offshore wind energy (OWE) is a cornerstone of future clean energy development. Yet, research into global OWE material demand has generally been limited to few materials and/or low technological resolution. In this study, we assess the primary raw material demand and secondary material supply of global OWE. It includes a wide assortment of...article 2022
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Wagenaar, J.W. (author)This chapter addresses met mast measurements for wind turbine wake research, where we tackle the matter by posing and answering three questions. By asking ourselves what the value is of met mast measurements for wake/aerodynamic research, we describe how met masts can be and have been used in aerodynamic research, accompanied by a number of...bookPart 2021
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Shankar Verma, A. (author), Jiang, Z. (author), Ren, Z. (author), Caboni, M. (author), Verhoef, H. (author), van der Mijle-Meijer, H. (author), Castro, S.G.P. (author), Teuwen J.J.E., (author)Rain-induced leading-edge erosion (LEE) of wind turbine blades (WTBs) is associated with high repair and maintenance costs. The effects of LEE can be triggered in less than 1 to 2 years for some wind turbine sites, whereas it may take several years for others. In addition, the growth of erosion may also differ for different blades and turbines...article 2021
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Schepers, J.G. (author)This chapter discusses several aspects related to engineering methods in wind tur bine design codes. Current engineering models for rotor aerodynamics topic are built around the Blade Element Momentum (BEM) theory. The Blade Element Momentum theory in itself is very basic, e.g., it is derived for two-dimensional, stationary, homogenous, and non...bookPart 2021
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Neunaber, I. (author), Holling, M. (author), Stevens, R.J.A.M. (author), Schepers, J.G. (author), Peinke, J. (author)Wind turbines are usually clustered in wind farms which causes the downstream turbines to operate in the turbulent wakes of upstream turbines. As turbulence is directly related to increased fatigue loads, knowledge of the turbulence in the wake and its evolution are important. Therefore, the main objective of this study is a comprehensive...article 2020
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Kumar, P. (author), Sanderse, B. (author), Boorsma, K. (author), Caboni, M. (author)A framework is presented for performing global sensitivity analysis of model parameters associated with the Blade Element Momentum (BEM) models. Sobol indices based on adaptive sparse polynomial expansions are used as a measure of global sensitivities. The sensitivity analysis workflow is developed using the uncertainty quantification toolbox...conference paper 2020
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Engels, W.P. (author), van der Hoek, D. (author), Yu, W. (author), Reyes Baez, R. (author)Many wind turbines are still controlled using gain scheduled, PI(D) controllers. Another option is to use a state feedback controller, such as LQG control. However, for wind turbines that is not straight forward solution, because the system is non-linear and the impact of pitching on the states varies in time. This paper presents a variation on...conference paper 2020
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Micallef, D. (author), Ferreiria, C. (author), Herráez, L. (author), Höning, L. (author), Yu, W. (author), Capdevila, H. (author)Navier-Stokes actuator disc models have become a mature methodology for investigating wind turbine rotor performance with numerous articles published annually making use of this approach. Despite their popularity, their ability to predict near wake expansion remains questionable. The objective of this paper is to analyse the predictive ability...article 2020
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Kanev, S. (author)Active wake control (AWC) is an operational strategy for wind farms that aims at reducing the negative effects of wakes behind wind turbines on the power production and mechanical loads at the wind turbines' downstream. For a given wind direction, the strategy relies on collaborative control of the machines within each row of turbines that...article 2019
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Ravishanara, A.K. (author), Ozdemir, H. (author), Franco, A. (author)In this study a new approach to model the effect of vortex generators in integral boundary layer equations is described. Vortex generators (VGs) are commonly used on wind turbine blades to avoid early separation of flow which helps not only to increase the lift but also delays the stall. Delaying the stall angle of wind turbine blades will allow...conference paper 2019
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Spectral analysis of New MEXICO standstill measurements to investigate vortex shedding in deep stallKhan, M.A. (author), Simão Ferreira, C. (author), Schepers, G.J. (author), Sørensen, N.N. (author)Spectral analysis was performed on the time series data computed from pressure measurements on the New MEXICO (Model Rotor Experiments under Controlled Conditions) rotor in standstill conditions. As a priori, 3D airfoil polars were recreated from standstill measurements and compared against 2D airfoil polars and flat plate theory results to...article 2019
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Zeron, V. (author), Wagenaar, J.W. (author), Wachter, M. (author)In this paper, a comparison is made between the four different power performance analysis methods as specified in the recently issued IEC 61400-12-1 edition 2, 2017 standard on “Power performance measurements of electricity producing wind turbines”. These methods include various combinations of meteorological mast and/or remote sensing device ...conference paper 2018
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Dragt, R.C. (author), Hengeveld, S.T. (author), Maljaars, J. (author)Measurements at Offshore Wind Turbine (OWT) substructures show that typical loading patterns include overloads, underloads, and shifts in mean stress cycles, due to the everchanging wind direction. These events follow each other in time and are further expressed as load sequences. Load sequences may affect the fatigue life. A novel model...conference paper 2018
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Boorsma, K. (author), Greco, L. (author), Bedon, G. (author)Results from the EU AVATAR project have indicated vortex methods generally to be in good agreement with computational fluid dynamics simulations for resolving rotor aerodynamic forces in a variety of operational and inflow conditions. Limitations of the more crude blade element momentum method, most widely used in industry, have been exposed....conference paper 2018
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Courage, W.M.G. (author), Nicoreac, M.P. (author), Kempker, P.L. (author)For offshore wind turbines (OWT’s) environmental and accessibility conditions make inspection and maintenance costly. Hence the potential of cost reduction when the planning of these actions can be optimized. Taking uncertainties into account, a risk based concept is adopted in which probabilities of failure and its consequences are balanced...conference paper 2017
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Dragt, R.C. (author), Maljaars, J. (author), Tuitman, J.T. (author), Salman, Y. (author), Otheguy, M.E. (author)Retardation is a load sequence effect, which causes a reduced fatigue crack growth rate after an overload is encountered. Retardation can be cancelled when the overload is followed by an underload. The net effect is beneficial to the fatigue lifetime of Offshore Wind Turbines (OWTs). To be able to take this into account, computationally...conference paper 2016
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- Jansen, E. (author), De Jong, C. (author) conference paper 2016