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Caldeira, Rui M. A.; Stegner, Alexandre; Couvelard, Xavier; Araujo, Isabel B.; Testor, Pierre; Lorenzo, Alvaro. |
Island wakes are areas of a strong eddy activity influencing the availability and transport of organic matter in the ocean which, in turn impact biological productivity. Despite this, eddy formation in the lee of North Atlantic tropical islands is scarcely documented, except for the Canary Islands. Moreover, the occurrence of anticyclones leeward of Madeira has seldom been detected. During the summer of 2011, a multiplatform approach, combining satellite data with in situ measurements, was used to study an anticyclonic eddy generated in the lee of the Madeira Island. The main objective was to confirm recent numerical evidence suggesting that orographically perturbed winds can induce anticyclonic eddies leeward of Madeira, particularly during summer months.... |
Tipo: Text |
Palavras-chave: Boundary-layer; Inertial instability; Mode water; Mixed layer; Intrathermocline eddies; Wake. |
Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00197/30846/29209.pdf |
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Mycek, Paul; Gaurier, Benoit; Germain, Gregory; Pinon, Gregory; Rivoalen, Elie. |
The ambient turbulence intensity in the upstream flow plays a decisive role in the behaviour of horizontal axis marine current turbines. Experimental trials, run in the IFREMER flume tank in Boulogne-Sur-Mer (France) for two different turbulence intensity rates, namely 3% and 15%, are presented. They show, for the studied turbine configuration, that while the wake of the turbine is deeply influenced by the ambient turbulence conditions, its mean performances turn out to be slightly modified. The presented conclusions are crucial in the view of implanting second generation turbines arrays. In addition, complete and detailed data sets (wake profiles and performance graphs) are made available to the scientific community in order to encourage further... |
Tipo: Text |
Palavras-chave: Marine current turbine; Performance; Wake; Turbulence; Experiment; Flume tank. |
Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00175/28647/27171.pdf |
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Mycek, Paul; Gaurier, Benoit; Germain, Gregory; Pinon, Gregory; Rivoalen, Elie. |
The future implantation of second generation marine current turbine arrays depends on the understanding of the negative interaction effects that exist between turbines in close proximity. This is especially the case when the turbines are axially aligned one behind another in the flow. In order to highlight these interaction effects, experiments were performed in a flume tank on 3-bladed 1/30th scale prototypes of horizontal axis turbines. This work focuses on the interactions between two horizontal axis marine current turbines, axially aligned with the upstream flow. Thrust and power coefficients function of the rotation speed of the downstream device are presented. Besides, the wake of each turbine is characterised so as to explain their behaviour. A... |
Tipo: Text |
Palavras-chave: Marine current turbine; Performance; Wake; Turbulence; Array; Tidal turbine. |
Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00175/28644/27110.pdf |
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Pinon, Gregory; Mycek, Paul; Germain, Gregory; Rivoalen, Elie. |
This paper presents numerical computations of three bladed horizontal axis marine current turbines in a uniform free upstream current. The unsteady evolution of the turbine wake is taken into account by some three-dimensional software, developed to assess the disturbances generated in the sea. An unsteady Lagrangian method is considered for these computations using "Vortex Method": a velocity-vorticity numerical implementation of the Navier-Stokes equations. The vortex flow is discretised with particles carrying vorticity, which are advected in a Lagrangian frame. The present paper aims at presenting results on both power and thrust coefficient (C-p and C-T) predictions and wake characterisation, up to ten diameters downstream of the turbine. Moreover, two... |
Tipo: Text |
Palavras-chave: Numerical computations; Marine current turbine; Hydrodynamic; Power and thrust coefficients; Wake. |
Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00087/19853/17616.pdf |
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