Searched for: subject%3A%22stall%22
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Timmer, W.A. (author), Bak, Christian (author)
This chapter focuses on airfoils for wind turbine blades and their characteristics. The use of panel codes such as XFOIL and RFOIL and CFD codes for the prediction of airfoil characteristics is briefly described. This chapter then discusses the requirements for wind turbine blade airfoils and the effect of leading edge roughness and Reynolds...
book chapter 2023
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Barrett, R. (author), Corpening, J. (author), Reasonover, C. (author)
This paper describes a new method for drag elimination and stall suppression via tangential synthetic jet actuators. This boundary layer control (BLC) method is shown to perform as well as continuous and normal synthetic jet BLC methods but without fouling difficulties, system-level complexity or extreme sensitivity to Reynolds number. Classical...
conference paper 2005
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Sarkar, S. (author), Bijl, H. (author)
In this paper the aeroelastic stability of a wind turbine rotor in the dynamic stall regime is investigated. Increased flexibility of modern turbine blades makes them more susceptible to aeroelastic instabilities. Complex oscillation modes like flap/lead-lag are of particular concern, which give way to potential structural damage, see...
conference paper 2006
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Sarkar, S. (author), Bijl, H. (author)
In this paper the aeroelastic stability of a wind turbine rotor in the dynamic stall regime is investigated. Increased flexibility of modern turbine blades makes them more susceptible to aeroelastic instabilities. Complex oscillation modes like flap/lead-lag are of particular concern, which give way to potential structural damage, see...
conference paper 2006
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Baldacchino, D. (author)
Vortex generators have become a ubiquitous sight on the modern wind turbine blade. These small, passive devices can increase the energy extraction potential of a rotor, but their subtle footprint disguises the technical difficulties associated with designing and integrating them onto wind turbine blades. The complexity of rotor inflow and the...
doctoral thesis 2019
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Balbino dos Santos Pereira, R. (author)
The contribution of sustainable Wind Energy (WE) to the global energy scenario has been steadily increasing over the past decades. In the process, Horizontal Axis Wind Turbines (HAWT) became the most widespread and largest WE harvesting machines. Nevertheless, significant challenges still lie ahead of further expansion of HAWT, namely concerning...
doctoral thesis 2016
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Ferede, E.A. (author)
There is a growth in the energy consumption of the world, leading to rapid depletion of natural resources, such as fossil fuels. Added to that, the environmental impact of fossil fuels (e.g. global warming) makes a renewable source of energy a better alternative for power generation. Among renewable energy sources, generating energy from wind is...
doctoral thesis 2016
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Sant, A. (author), Van Kuik, G.A.M. (author), Van Bussel, G.J.W. (author)
journal article 2008
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De Tavernier, D. (author), Ferreira, Carlos (author), Viré, A.C. (author), LeBlanc, B.P. (author), Bernardy, S. (author)
Vortex generators (VGs) have proven their capabilities in wind turbine applications to delay stall in steady flow conditions. However, their behaviour in unsteady conditions is insufficiently understood. This paper presents an experimental study that demonstrates the effect of VGs in unsteady flow, including controlling and suppressing the...
journal article 2021
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Boatto, Umberto (author), Bonnet, Paul A. (author), Avallone, F. (author), Ragni, D. (author)
Blade Element Momentum Theory (BEMT) -based approaches provide 15%–20% inaccurate load predictions under uniform steady inflow. Inaccuracies were related to unclear aerodynamic mechanisms causing the Prandtl Tip-Root Loss (TRL) correction to fail at high Tip-Speed Ratio (TSR) and the ambiguous drag coefficient treatment under Stall Delay (SD)...
journal article 2023
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Yu, W. (author), Bajarūnas, Lukas K. (author), Zanon, Alessandro (author), Ferreira, Carlos J.S. (author)
Vortex generators (VGs) have been widely applied to wind turbines thanks to their potential to increase aerodynamic performance. Due to the complex inflow perceived by a rotor and the proneness to flow separation, VGs on wind turbines usually experience highly unsteady flow. While there are models that exist to simulate the steady effects of...
journal article 2024
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Wani, F.M. (author), Shipurkar, U. (author), Dong, J. (author), Polinder, H. (author), Jarquin Laguna, A. (author), Mostafa, Kaswar (author), Lavidas, G. (author)
Thermal cycling is one of the major reasons for failure in power electronic converters. For submerged tidal turbine converters investigating this failure mode is critical in improving the reliability, and minimizing the cost of energy from tidal turbines. This paper considers a submerged tidal turbine converter which is passively cooled by...
journal article 2020
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Mendoza, Victor (author), Bachant, Peter (author), Ferreira, Carlos (author), Goude, Anders (author)
In the present work, the near-wake generated for a vertical axis wind turbine (VAWT) was simulated using an actuator line model (ALM) in order to validate and evaluate its accuracy. The sensitivity of the model to the variation of the spatial and temporal discretization was studied and showed a bigger response to the variation in the mesh size...
journal article 2019
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Khan, Muhammad A. (author), Ferreira, Carlos (author), Schepers, J.G. (author), Sørensen, Niels 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...
journal article 2019
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Timmer, W.A. (author)
A relatively simple method is presented to predict the maximum two-dimensional drag coefficient of an airfoil only using its shape. The method is based on a contribution related to the leading edge thickness in terms of the y/c coordinate at x/c=0.0125 and a contribution related to the trailing edge flow angle which appears also to be...
journal article 2020
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van Ingen, Joost (author)
From 2019 onwards, airline pilots will be required to follow stall training in simulators. A major open research question is which level of model fidelity is required for effective training. As part of an effort to answer this question, a stall model of a Cessna Citation II aircraft is developed from specifically-gathered flight test data. The...
master thesis 2017
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Faber, Mark (author)
Aeroelastic codes are fundamental for the design of wind turbines and the prediction of instabilities. Such codes rely on engineering models which limit their accuracy. With wind turbine blades becoming more slender to lower the costs, it is important to reduce these uncertainties to maintain a safe and stable turbine design. The dynamic stall...
master thesis 2018
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Fernandez Barrio, Jorge (author)
A proportionate controller is investigated experimentally for unsteady load alleviation purposes on a 2D wing model with a trailing edge flap. This study is supposed to be a simplified version of a Smart Rotor, a mechanism which deals with the reduction of unsteady loads acting on a wind turbine and aims to understand the behavior of this type...
master thesis 2020
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van Horssen, L.J. (author)
In 2019 all air-carrier pilots are obliged to go through flight simulator-based stall recovery training. Therefore simulators will have to be equipped with accurate flight models at high angles of attack. This research shows which stall characteristics can be modeled using flight data from symmetrical induced, quasi-steady stalls. Furthermore a...
master thesis 2016
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De Voogt, Francis (author)
Stall is traditionally divided in three types of stall behaviour, these have been regarded as two dimensional and dominated by the airfoil shape. However one of these types of stall behaviour, trailing edge stall, has been shown in literature to be three dimensional by forming stall cells along the wing span. Stall cells are coherent flow...
master thesis 2019
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