Abstract
The present study carries out numerical and experimental investigations on the performance of a vertical axis tidal current turbine of drag force type (Savonius turbine). For the performance test, firstly, various numbers of turbine blades are tested. Secondly, the turbine with double layered blades were tested and compared with the one with a single layer. The vertical axis turbine in this study has arch-shaped blades. While the numerical simulations were conducted with a commercial computational fluid dynamics (CFD) program, the experiments were conducted in a circulating water channel. From both approaches, parameters representing the performance of the turbine such as power coefficient and torque are examined. The number of blades and layers which is closely related to the drag force seems important to the Savonius turbine. Based on the validation between the experiments and the numerical simulations, the numerical tests were extended to examine the performance from various cases. The influence of the layer height was also discussed from the experimental results.