Unsteady flow through the gap of savonius turbine rotor

The paper presents a numerical analysis of unsteady flow through the gap of a Savonius turbine rotor, performed for varying integral turbine operating parameters calculated for the case under study as well as obtained from experiments described in the literature. Changes in the unsteady flow pattern, including the development and interaction of numerous vortex structures in the vicinity of the gap, and their relevance to the varying integral parameters are discussed. We conclude that the structure responsible for the intensity of the flow through the gap is a vortex which forms in the vicinity of the gap at certain phases of rotor revolution, and that a possible way to improve the efficiency of operation of a Savonius turbine is to control the intensity of this vortex by modifying the shape of the blade edges in the vicinity of the gap.