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Abstract: This paper treats the vortex shedding phenomenon of a savonius wind turbine, whose knowledge is primordial in correctly calculating the airloads on the blades. The specific aim being to numerically predict the disposition and geometry of the vortical structures in the wake of the savonius rotor whose existence has been visualised by a number of experimentalists. In the numerical approach, the blade is represented by discrete bound vortices while the wake is generated in a time stepping calculation as an emission of free vortices. The calculations are enhanced by the Newmann boundary condition coupled to the Kutta–Joukowsky condition and the Kelvin's theorem for the conservation of circulation. The convection of the vortices in the wake is accomplished through a predictor corrector integration scheme. A code has been developed which predicts the wake structure to be in good agreement with the experimental visualizations: For low tip speed ratios, the wake consists of a series of three discrete vortical structures while at higher tip speed ratios, the characteristic structure is the presences of a central vortex. [Copyright &y& Elsevier]

Abstract: The aim of this paper is to numerically explore the non-linear two-dimensional unsteady potential flow over a Savonius rotor and to develop a code for predicting its aerodynamics performances. In the model developed, the rotor is represented in a median plane by two semicircles, displaced along their common diameter. The two semicircles can be considered to produce lifting effects. As a result, they are modelled by a collection of discrete vortices on their contours. The flow field is then governed by the Laplace equation. The versatile Neumann boundary condition, applied over the contour of the semicircles and the Kutta Joukowsky condition applied at the four extremities of the semicircles have been used in the modelling. The torque distribution of the stationary rotor and the unsteady pressure field on the blades of the rotating rotor, predicted by the code developed, have been compared and validated by some experimental data. [Copyright &y& Elsevier]

One of attracting concepts has been the use of Turbosail principle to produce lift from aspirated cylinders with flap in various engineering applications. The Emerging of the Turbosail principle in wind turbine technology is promising to develop and to design innovative devices. The objective of this project paper is to develop an efficient numerical code, for the prediction of the aerodynamic characteristics of Turbosail type wind turbine with very thick aspirated profiles. A vortex model has been treated based on the lifting line theory. The results predicted by the code developed, have been compared and validated by some numerical and experimental data. [ABSTRACT FROM AUTHOR]