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Baldacchino, D. (author), Ferreira, Carlos (author), De Tavernier, D. (author), Timmer, W.A. (author), van Bussel, G.J.W. (author)Passive vane-type vortex generators (VGs) are commonly used on wind turbine blades to mitigate the effects of flow separation. However, significant uncertainty surrounds VG design guidelines. Understanding the influence of VG parameters on airfoil performance requires a systematic approach targeting wind energy-specific airfoils. Thus, the 30...journal article 2018
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Koppejan, V.W. (author), Ferreira, Guilherme (author), Lin, Dong Qiang (author), Ottens, M. (author)Expanded bed adsorption (EBA) emerged in the early 1990s in an attempt to integrate the clarification, capture and initial product concentration/purification process. Several mathematical models have been put forward to describe its operation. However, none of the models developed specifically for EBA allows simultaneous prediction of bed...journal article 2018
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Huijs, Fons (author), Vlasveld, Ebert (author), Gormand, Maël (author), Savenije, F.J. (author), Caboni, Marco (author), LeBlanc, B.P. (author), Ferreira, Carlos (author), Lindenburg, Koert (author)A semi-submersible Tri-Floater has been designed to support a 6 MW vertical axis wind turbine (VAWT) with active blade pitch control. Due to the low centre of gravity and large allowable floater tilt angle, a relatively small floater can be used to support a VAWT. Coupled simulations including hydrodynamics, mooring system, aerodynamics and...journal article 2018
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Shen, Y. (author), Wang, Jinguo (author), Lindenbergh, R.C. (author), Hofland, Bas (author), Ferreira, Vagner G. (author)The use of a terrestrial laser scanner is examined to measure the changes of rock slopes subject to a wave attack test. Real scenarios are simulated in a water flume facility using a wave attack experiment representing a storm of 3000 waves. The stability of two rock slopes of different steepness was evaluated under the set conditions. For...journal article 2018
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Shipurkar, U. (author), Dong, J. (author), Polinder, H. (author), Ferreira, Jan Abraham (author)Modularity is promising from a view to increasing turbine availability through fault tolerant operation as well as reduced downtimes, especially for offshore wind turbines. This paper focuses on a quantitative analysis of large scale (or extreme) modularity in power electronic converters of wind turbine generator systems. It uses mathematical...journal article 2018
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Yu, W. (author), Hong, V.W. (author), Ferreira, Carlos (author), van Kuik, G.A.M. (author)The Blade Element Momentum model, which is based on the actuator disc theory, is still the model most used for the design of open rotors. Although derived from steady cases with a fully developed wake, this approach is also applied to unsteady cases, with additional engineering corrections. This work aims to study the impact of an unsteady...journal article 2017
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Hailu, T.G. (author), Mackay, L.J. (author), Ramirez Elizondo, L.M. (author), Ferreira, Jan Abraham (author)This paper describes the behavior of voltage weak DC distribution systems. These systems have relatively small system capacitance. The size of system capacitance, which stores energy, has a considerable effect on the value of fault currents, control complexity, and system reliability. A number of potential definitions of voltage weak DC...journal article 2017
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Liu, D. (author), Polinder, H. (author), Abrahamsen, Asger B. (author), Ferreira, Jan Abraham (author)This paper aims at assessing the potential of partially superconducting generators for 10 MW direct-drive wind turbines by investigating their performance for a very wide range of excitation currents. Performance indicators such as shear stress and efficiency and other generator characteristics are compared for 12 different generator topologies....journal article 2017
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Prasanth, V. (author), Bandyopadhyay, S. (author), Bauer, P. (author), Ferreira, Jan Abraham (author)This paper deals with a generic methodology to evaluate the magnetic parameters of contactless power transfer systems. Neumann's integral has been used to create a matrix method that can model the magnetics of single coils (circle, square, rectangle). The principle of superposition has been utilized to extend the theory to multi-coil...journal article 2017
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Ragni, D. (author), Ferreira, Carlos (author)A 3D stall-cell flow-field has been studied in a 4.8 aspect-ratio wing obtained by linear extrusion of a laminar NACA64-418 airfoil profile. The span-wise change in the velocity and pressure distribution along the wing has been quantified with respect to the development of cellular structures from 8◦ to 20◦ angle of attack. Oil-flow...journal article 2017
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Micallef, D. (author), Sant, Tonio (author), Ferreira, Carlos (author)The performance of a wind turbine located above a cubic building is not well understood. This issue is of fundamental importance for the design of small scale wind turbines. One variable which is of particular importance in this respect is the turbine height above roof level. In this work, the power performance of a small wind turbine is...journal article 2016
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Ferreira, Carlos (author), Gonzalez, A. (author), Baldacchino, D. (author), Aparicio, M. (author), Gomez, S (author), Munduate, X. (author), Garcia, N. R. (author), Sørensen, J. N. (author), Jost, E. (author), Knecht, S. (author), Lutz, T. (author), Chassapogiannis, P. (author), Diakakis, K. (author), Papadakis, G. (author), Voutsinas, S. (author), Prospathopoulos, J. (author), Gillebaart, T. (author), van Zuijlen, A.H. (author)The FP7 AdVanced Aerodynamic Tools for lArge Rotors - Avatar project aims to develop and validate advanced aerodynamic models, to be used in integral design codes for the next generation of large scale wind turbines (10-20MW). One of the approaches towards reaching rotors for 10-20MW size is the application of flow control devices, such as...journal article 2016
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Ceyhan, J. G Schepers O (author), Ceyhan, O (author), Boorsma, K. (author), Gonzalez, A. (author), Munduate, X. (author), Pires, O. (author), Sørensen, N. (author), Ferreira, Carlos (author), Sieros, G. (author), Madsen, J. (author), Voutsinas, S. (author), Lutz, T. (author), Barakos, G. (author), Colonia, S. (author), Heißelmann, H. (author), Meng, F. (author), Croce, A. (author)This paper presents the most recent results from the EU project AVATAR in which aerodynamic models are improved and validated for wind turbines on a scale of 10 MW and more. Measurements on a DU 00-W-212 airfoil are presented which have been taken in the pressurized DNW-HDG wind tunnel up to a Reynolds number of 15 Million. These measurements...journal article 2016
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Sørensen, Niels N. (author), Méndez, B. (author), Muñoz, A. (author), Sieros, G. (author), Jost, E. (author), Lutz, T. (author), Papadakis, G. (author), Voutsinas, S. (author), Barakos, G. N. (author), Colonia, S. (author), Baldacchino, D. (author), Baptista, C.F. (author), Ferreira, Carlos (author)The current paper presents the effort, in the EU AVATAR project, to establish the necessary requirements to obtain consistent lift over drag ratios among seven CFD codes. The flow around a 2D airfoil case is studied, for both transitional and fully turbulent conditions at Reynolds numbers of 3 × 10<sup>6</sup> and 15 × 10<sup>6</sup>. The...journal article 2016
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Strous, T.D. (author), Shipurkar, U. (author), Polinder, H. (author), Ferreira, Jan Abraham (author)In this paper, the brushless DFIM based wind turbine drive-train topology is compared to the DFIG based and PM generator based drive-train topologies, that are most commonly applied in modern wind turbines. The comparison will be based on a 3:2MW case study wind turbine. By using FE based multi-objective optimization, optimized generator designs...journal article 2016
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Sant, T. (author), Del Campo, V. (author), Micallef, D. (author), Ferreira, Carlos (author)Lifting line vortex models have been widely used to predict flow fields around wind turbine rotors. Such models are known to be deficient in modelling flow fields close to the blades due to the assumption that blade vorticity is concentrated on a line and consequently the influences of blade geometry are not well captured. The present study...journal article 2016
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Shipurkar, U. (author), Polinder, H. (author), Ferreira, Jan Abraham (author)Availability is an important factor to be considered when designing wind turbine generator systems. The quest for increasing availability is based on the following five design approaches - design for component reliability, active control for reliability, design for fault tolerance, prognostics, and design for maintainability. This paper reviews...journal article 2016
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Baldacchino, D. (author), M Manolesos, M. (author), Ferreira, Carlos (author), Gonzalez Salcedo, A (author), Aparicio, M. (author), Chaviaropoulos, T. (author), Diakakis, K. (author), Florentie, L. (author), Garcia, M. (author), Papadakis, G (author), Sorensen, N.N. (author), Timmer, W.A. (author), Troldborg, N. (author), Voutsinas, S. (author), van Zuijlen, A.H. (author)Experimental results and complimentary computations for airfoils with vortex generators are compared in this paper, as part of an e_ort within the AVATAR project to develop tools for wind turbine blade control devices. Measurements from two airfoils equipped with passive vortex generators, a 30% thick DU97W300 and an 18% thick NTUA T18 have been...journal article 2016
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Berdowski, T.J. (author), Walther, J. (author), Ferreira, Carlos (author), Meng, F. (author)In the current paper, a method for deriving the analytical expressions for the velocity and vortex stretching terms as a function of the spherical multipole expansion approximation of the vector potential is presented. These terms are essential in the context of 3D Lagrangian vortex particle methods combined with fast summation techniques. The...journal article 2016
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3D Lagrangian VPM: Simulations of the near-wake of an actuator disc and horizontal axis wind turbineBerdowski, T.J. (author), Ferreira, Carlos (author), Walther, J. (author)The application of a 3-dimensional Lagrangian vortex particle method has been assessed for modelling the near-wake of an axisymmetrical actuator disc and 3-bladed horizontal axis wind turbine with prescribed circulation from the MEXICO (Model EXperiments In COntrolled conditions) experiment. The method was developed in the framework of the open-...journal article 2016