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Although the Magnus type wind turbine has many benefits over conventional blade-type wind turbines, it normally has low wind energy utilization efficiency. Therefore, it is important to seek effective ways of improving the Magnus wind turbine power performance in order to promote its application. As blade aspect ratio is a critical parameter influencing the Magnus wind turbine performance, a 3D numerical study of a Magnus type wind turbine which is equipped with cylindrical blades with different aspect ratios has been conducted in this paper. In addition, various cylinder shapes, including truncated cone and wavy cylinder, have also been used and their effects on the performance of the Magnus wind turbine are analyzed. Performance characteristics such as power, torque, and thrust coefficients of the Magnus turbine with different blade shapes are compared and discussed with the aim of identifying the desirable blade characteristics for this type of turbine. V C 2012 American Institute of Physics.

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Pressure, density, and temperature are the fundamental thermodynamic parameters. In a liquid flow field, once the local pressure drops to the saturated pressure, the liquid vapourizes and local cavitation occurs. The cavitation region of the flow is characterized by a mixture of liquid and vapour. Vapourization is an endothermic process. However, in the literature of the past several decades, this vapourization induced thermal effect was sometimes ignored in cavitating flows, and the temperature was always assumed as a constant in the whole flow field. In order to gain a deep insight into the mechanism of cavitation, temperature effects of cavitation are hereby investigated in this paper. An appreciable temperature drop has been found when cavitation occurs, which suggests that thermal effects in cavitating flows from the view of thermodynamics may be of great value to understand the mechanism of cavitation.