The combination of Savonius and Darrieus turbines had been proposed with the aim to overcome the weaknesses and complement the strengths from each design. This paper gathers relevant information and provided an extensive review on the combined Savonius-Darrieus turbine for both wind and hydro applications. The paper initially reviews the experimental and computational methodologies utilized in previous research in design evaluation of the turbines. The self-starting capability and efficiency of both turbines were the main concern. Following this, investigations were conducted on the possibility of combining the advantages on the two turbines with respect on the design compactness, radius ratios, attachment angles and rotational velocities.

Most wetland rice production schemes have good networks of irrigation and drainage canals built for the benefit of the farmers to perform farming activities. The canals have ample volume of running water all year round and could be harnessed for hydropower. The Savonius hydrokinetic turbine has been generally used to generate electrical energy as the means of renewable source over fossil fuels. Numerous parameters have been studied to enhance the performance of the turbine. However, the turbine power performance is still low as compared to other types even though it is known to have excellent torque characteristics. Therefore, the objectives of this study are to evaluate the effects of a central shaft and a guiding wall on the performances of the Savonius hydrokinetic turbines by using two-dimensional computational simulations. ANSYS Fluent software with the standard k-ε turbulence model and dynamic mesh motion techniques were used to get the optimum central shaft and guiding wall configurations. The central shaft was studied in three cases; (I) with a full shaft, (II) with a shaft and space, and (III) without shaft between two end plates. Moreover, the turbine performances were also evaluated with and without the presence of a guiding wall. The turbine performances were computed. Simulation results e.g. velocity, pressure contours and flow structures across a SHKT model were analysed and discussed.