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ABSTRACT. DYNAMIC STALL PHENOMENON IN VERTICAL AXIS WIND TURBINE (VAWT) IS ANALYZED BY SEMI-EMPIRICAL MODELS. SOME EXISTING MODELS, THE BOEING-VERTOL, MIT AND INDICIAL ARE REVISED AND PROPOSED THE UTILIZATION OF A MODIFIED ONERA MODEL WITH IMPROVED PERFORMANCE. THE MODEL IS BASED ON A SET OF DIFFERENTIAL EQUATIONS THAT PERMIT TO MODEL THE COMPONENTS OF THE LIFT AND DRAG COEFFICIENTS AT DYNAMIC STALL. THE RESULTS OF THE AERODYNAMIC FORCES ARE PRESENTED WITH THE PROPOSED MODEL, AFTER REALIZING MODIFICATIONS THAT PERMIT IT TO EXTEND OPERATION AT LOW TIP SPEED RATIO WHERE THE AMPLITUDE OF OSCILLATION OF THE ANGLE OF ATTACK HIGH. THE RESULTS ARE COMPARED WITH THE EXPERIMENT SHOWING A GOOD AGREEMENT. FINALLY, THE ADVANTAGE, EASINESS AND LIMITATIONS OF THE PROPOSED ARE ANALIZED METHODOLOGY.
KEYWORDS: STALL DYNAMIC, UNSTEADY AERODYNAMICS.
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