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Dahlmann, K. (author), Matthes, Sigrun (author), Yamashita, H. (author), Unterstrasser, S. (author), Grewe, V. (author), Marks, Tobias (author)An operational measure to aim for mitigation of aviation climate impact that is inspired by migrant birds is to fly in aerodynamic formation. This operational measure adapted to human aircraft would eventually save fuel and is, therefore, expected to reduce the climate impact of aviation. As this method changes beside the total emission also the...abstract 2020
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Yeh, Jefferson (author)Wind energy, generated by windfarms, is playing an increasingly critical role in meeting current and future energy demands. windfarms, however, face a challenge due to the inherent flaw of wake-induced power losses when turbines are located in close proximity. Wakes, characterized by regions of turbulence and lower wind speed, are created as air...bachelor thesis 2023
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van Selm, Jasper (author)When multiple wind turbines are positioned close to one another, such as in a wind farm, wind turbines located downwind of other turbines are not 100% efficient due to wakes, negatively affecting the total power output of the wind farm. A way to mitigate the loss of power is to steer the wake away from the next turbine, which lowers the current...bachelor thesis 2023
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Filimon, Mihai (author)The close proximity of wind turbines to one another in a wind farm can lead to inefficiency in terms of power production due to wake effects. One technique to mitigate the losses is to veer from their individual optimal direction. As such, the wakes can be steered away from downstream turbines in order to increase the overall power output. Multi...bachelor thesis 2023
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van der Schaaf, Guus (author)In wind farms wind turbines are often placed close to each other. Each turbine generates a turbulent wake field, this field negatively affects subsequent turbines. This can cost more than 12% efficiency. To decrease this loss we can steer the turbines away from the wind direction, this will decrease the individual turbine power output, but can...bachelor thesis 2023
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Steinebach, Koen (author)The wind energy industry is growing more than ever before and wind energy as a renewable energy source has shown quite a potential over the years. Unfortunately, the power yield of a wind farm can fluctuate largely over time, which originates from fluctuating wind speed magnitudes. Convection of air, turbulence, humidity and radiation of heat are...bachelor thesis 2017
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Plămădeală, Ion (author)The wake effect which is turbulence behind a wind turbine created when it extracts energy negatively impacts the power output of the downstream turbines. Active Wake Control can mitigate this effect, by rotating some turbines away from the wind. Previous research applied single agent reinforcement learning to apply Active Wake Control, show- ing...bachelor thesis 2023
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De Tavernier, D. (author), Ferreira, Carlos (author), Goude, Anders (author)This chapter highlights the main aerodynamic phenomena and challenges of vertical-axis wind turbines. First, an introduction is provided on the VAWT history and (dis-)advantages. The basics of VAWT aerodynamics and the various rotor simplifications/representations are presented. Further, the state-of-the art aerodynamic modeling techniques,...book chapter 2022
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Coustols, E. (author), Jacquin, L. (author), Schrauf, G. (author)This document provides a synthesis of recent research studies that have been conducted in the last decade within several European projects from the 5th and 6th Framework Programmes. All these studies aimed at a better characterization of aircraft wake vortices and then at their subsequent control. In the latter case, the goal is to minimize the...conference paper 2006
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Lignarolo, L. (author), Ragni, D. (author), Simao Ferreira, C.J. (author), van Bussel, G.J.W. (author)The present paper is the summary of 3 years of research on the wake aerodynamics of horizontal axis wind turbine at Delft University of Technology, the Netherlands. In particular, the main results and the conclusions of two experimental campaigns are collected. The underlying research question is: how do the near-wake turbulent flow structures...conference paper 2015
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Bae, Y. (author), Jang, J.Y. (author), Moon, Y.J. (author)In the present study, the effects of fluid-structure interaction (FSI) on the trailingedge noise are numerically investigated, particularly for the cases of wake instability and Karman vortex shedding. The trailing-edge is modelled as a flat plate with an elastic cantilever end and its flow-induced vibration is solved by an eigenmode analysis...conference paper 2006
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Van Kuik, G.A.M. (author), Van Zuijlen, A.H. (author)Actuator disc calculations can be divided in two categories: force models where, for a prescribed force field, the flow is calculated using a CFD method, and kinematic models, where the wake is calculated based on wake boundary conditions and the force field is known when the velocities are known. In both categories, but specifically for the...conference paper 2009
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- Dixon, K. (author), Simao Ferreira, C.J. (author), Hofemann, C. (author), Van Bussel, G.J.W. (author), Van Kuik, G.A.M. (author) conference paper 2008
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Jones, L.E. (author), Sandberg, R.D. (author), Sandham, N.D. (author)Direct numerical simulations of a NACA-0012 airfoil at zero degrees incidence are presented for a range of Mach and Reynolds numbers. At Reynolds number 10,000, the flow around the airfoil is found to be dominated by vortex shedding from an unstable wake. Frequencies are found to collapse using a Strouhal number based on trailing edge...conference paper 2006
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Fragoso Rodrigues, S.M. (author), Bauer, P. (author), Bosman, P.A.N. (author), Pierik, J. (author)Offshore wind farms with high installed capacities and located further from the shore are starting to be built by northern European countries. Furthermore, it is expected that by 2020, several dozens of large offshore wind farms will be built in the Baltic, Irish and North seas. These wind farms will be constituted of a considerable number of...conference paper 2014
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Gushchin, V.A. (author), Matyushin, P.V. (author)The homogeneous (1 < Re < 5000000) and stratified (0.004 < Fr < 1, 10 < Re < 1000) viscous incompressible fluid flows around a sphere have been investigated by means of the direct numerical simulation (DNS) and the visualization of the vortex structures in the wake. In case of the homogeneous fluid at 200 < Re < 1000 the detailed formation...conference paper 2006
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Hemida, H. (author), Krajnovic, S. (author)Large-eddy simulation (LES) is made to investigate the flow around a generic train under side wind conditions. Two different side-wind yaw angles are used in the investigation: 35 and 90 degrees. The Reynolds numbers based on the height of the train and the freestream velocity are 300,000 and 370,000 for the 90 and 35 degrees yaw angles,...conference paper 2006
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Micallef, D. (author), Akay, B. (author), Sant, T. (author), Simao Ferreira, C.J. (author), Van Bussel, G.J.W. (author)The scope of this work was to investigate radial flow component for a Horizontal Axis Wind Turbine in axial flow conditions and to assess its impact on the turbine operation. This was done by means of Particle Image Velocimetry and numerical simulation with a 3D unsteady potential-flow panel model. A direct comparison between the numerical and...conference paper 2011
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Voss, G. (author), Melber-Wilkending, S. (author), Rudnik, R. (author)This paper gives an overview of the research on wake vortex decay using Differential Flap Setting (DFS) and Oscillating Flap Setting (OFS). The concept of DFS deals with the small deflection of flaps and elevator to produce additional vortices which interacts with the vortices from wing, elevator, flaps and wing-body-junction. Numerical...conference paper 2006
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Veldhuis, L.L.M. (author), De Kat, R. (author)To get a better insight in the effect of jets on vortex development and decay, stereo-PIV measurements were performed in a towing tank behind a flapped aircraft model. The experimental data set yields the wake vortex behavior in a range that extends from the vortex formation stage up to the mid-field (approximately t* =2 corresponding to 100...conference paper 2008