Energy harvesting potential using a novel hybrid bladeless-Savonius wind turbine

This study investigates experimentally a novel hybrid wind energy system combining a bladeless wind turbine (BWT) with a Savonius rotor. While both technologies have been extensively studied in isolation, their aerodynamic interaction remains largely unexplored. Specifically, no prior work has systematically examined how the oscillatory wake from a BWT influences the inflow and torque characteristics of a Savonius rotor, or how the rotor induced turbulent wakes feeds back into BWT performance. Addressing this gap, the present research demonstrates that integrating the two technologies can substantially enhance overall energy harvesting. Experimental results show that Savonius rotor performance in the hybrid systems generally outperforms standalone Savonius one in the low tip-speed ratio regime, with efficiency gains of up to 20% in optimized BWT placements (e.g., B2, C2, and E2). However, suboptimal configurations reduce performance, highlighting the critical role of spatial arrangement in minimizing adverse wake effects. Integrating a Savonius rotor with a bladeless wind turbine, both in conventional configurations, and optimizing their spacing boosts the overall power coefficient by about 26% at the optimal tip-speed ratio, providing clear guidelines for device placement and future design improvements. Moreover, employing hybrid system operation besides increasing Reynolds number improves standalone Savonius turbine performance by about 16.5% and 27.5%, respectively. These findings establish the aerodynamic synergy of Bladeless–Savonius hybrids, providing new design strategies for feasible and efficient wind energy systems.