Enhanced Performance of Cross-Flow Savonius Turbines at Low Current Velocity: A Numerical Investigation on the Influence of Deflector Configurations

In Indonesia, ocean currents represent a promising resource and one technology that can be used to harness them is the Savonius turbine. Although the vertical-axis Savonius turbine has been widely explored due to its ability to operate at low flow velocities, research on the cross-flow type remains limited. This study analyzed the influence of adding a deflector and placement variations on the performance of a cross-flow Savonius turbine. The turbine was tested with several deflector configurations, including different distances 0.22, 0.23, 0.24, and 0.33 m from the turbine, to evaluate their influence on performance. The deflector was designed to redirect flow to avoid the returning blade while strengthening the advancing blade, thereby enhancing energy capture. A numerical investigation was conducted using Computational Fluid Dynamics (CFD). The results of adding the deflector significantly improved the turbine performance in terms of its torque (Ct) and power coefficients (Cp) by 44%. The optimal configuration was obtained at a deflector distance of 0.23 m with a Tip Speed Ratio (TSR) of 0.739, yielding a coefficient of power of 0.289. This study indicates that proper deflector positioning can effectively improve the performance of a cross-flow type Savonius turbine.