Amirkabir University of Technology Amirkabir Journal of Mechanical Engineering 2008-6032 51 2 2019 06 22 Turbulent Structures in the Wake of a Wind Turbine Using Large Eddy Simulation Turbulent Structures in the Wake of a Wind Turbine Using Large Eddy Simulation 261 280 2661 10.22060/mej.2017.12740.5420 FA A. Veisi Department of Mechanical Engineering, Sistan and Baluchestan University, Zahedan, Iran M.H. Shafiei Mayam Department of Mechanical Engineering, Bozorgmehr-University of Qaenat, Qaen, Iran Journal Article 2017 04 09 In the present work the flow around a horizontal axis wind turbine has been studiedusing large Eddy simulation at different rotational speeds. The results show increasing rotational speedscauses a higher velocity deficit in the downstream direction. For example, in 1D after the wind turbinethe minimum velocity is 54% of the initial velocity and reach to the 67% of the initial velocity after waketravel 6D. At the rotational speed of λ3= 10 the minimum velocity is 26% of the initial velocity and reachto the 68% of the initial velocity after wake travel 6D. The frequency of vortex shedding is increasedby increasing the rotational speeds. Shed vortices tend to be extended in the y direction and its intensityaugmented by increasing the rotational speeds. The strengthen of vortices at higher rotational directionin far wake region not only due to the increased of swirling strength, but it is also due to the collision ofvortices and the formation of new vortices. This issue has not been reported in previous works. Also, theincrease of turbulence intensity and Reynolds shear stress in the flow direction is due to the severe windshear and high mechanical production of turbulent kinetic energy. In the present work the flow around a horizontal axis wind turbine has been studiedusing large Eddy simulation at different rotational speeds. The results show increasing rotational speedscauses a higher velocity deficit in the downstream direction. For example, in 1D after the wind turbinethe minimum velocity is 54% of the initial velocity and reach to the 67% of the initial velocity after waketravel 6D. At the rotational speed of λ3= 10 the minimum velocity is 26% of the initial velocity and reachto the 68% of the initial velocity after wake travel 6D. The frequency of vortex shedding is increasedby increasing the rotational speeds. Shed vortices tend to be extended in the y direction and its intensityaugmented by increasing the rotational speeds. The strengthen of vortices at higher rotational directionin far wake region not only due to the increased of swirling strength, but it is also due to the collision ofvortices and the formation of new vortices. This issue has not been reported in previous works. Also, theincrease of turbulence intensity and Reynolds shear stress in the flow direction is due to the severe windshear and high mechanical production of turbulent kinetic energy.

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