FLOW OVER A STATIC 2D SAVONIUS ROTOR USING IMMERSED BOUNDARY AND FOURIER PSEUDOSPECTRAL METHODS

Savonius rotors are vertical-axis wind turbines characterized by their "S" shape, low speed, low noise, and effective startup capabilities. Composed of two semi-cylindrical blades, the rotation is initiated by the interaction of the fluid with the blade surfaces, generating combined torques. To enhance understanding of this turbine's behavior, this study presents a simplified model of the flow around the rotor using the Fourier Pseudospectral Method coupled with the Immersed Boundary Method. The model assumes an incompressible, Newtonian fluid with constant properties, no heat transfer or gravitational effects, and a two-dimensional analysis. The results, based on ReD = 200, evaluate the flow over the static rotor and show that the advancing blade has a higher drag coefficient at startup compared to the returning blade. This behavior suggests the rotor's direction of rotation under the pre-established flow conditions in an induced rotation.