Parametric Study of Tornado-Type Wind Energy Systems

    Research output: NRELTechnical Report


    The tornado-type wind energy system uses the pressure drop created by an intense vortex. The vortex is generated in a tower mounted at the turbine exit. The tower serves as a low pressure exhaust for the turbine. In a previous work, the author provided a numerical solution, using the two-equation (k-e) turbulence model, of the tower flow with a uniform wind flow. Results compared favorably withmeasured values of pressure and showed a turbine diameter of -0.4 times that of the; tower to be optimum. In the present work, the author provides results to show the effects of embedding the tower in an atmospheric boundary layer, varying the tower height to diameter ratio, and varying tower diameter using the same system geometry and approach flow conditions. The results indicate a reductionof -28% in power output caused by atmospheric boundary layer effects using a power low profile, a minimum height/diameter ratio of -1.0 to avoid asymmetric vortex decay, and decreasing improvements in system performance with increasing system size. For the latter, the results show a 23% increase in the power coefficient by increasing the tower diameter from 0.5 m to 1 .0 m, but only a 1%increase by increasing the tower diameter from 4 m to 8 m.
    Original languageAmerican English
    Number of pages15
    StatePublished - 1981

    NREL Publication Number

    • NREL/TP-211-1391


    • tornado-type wind energy systems
    • turbines
    • vortex


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