How does a Savonius turbine rotate in turbulence?

What is it about?

Savonius turbines are drag-driven vertical axis wind turbines (VAWTs). The primary advantages of VAWTs over horizontal-axis wind turbines (HAWTs) are to capture wind from all directions and their designs that seemlessly blend into urban landscapes. In addition, Savonius turbines are recognised for their resilience to turbulence, in contrast to lift-driven turbines that are prone to stall, which is a sudden decrease in lift. Savonius turbines are therefore often installed in urban areas characterised by highly turbulent winds caused by complex terrains. This paper investigates how high turbulence affects the rotation and the wake of the Savonius turbine through both experimental and theoretical approaches. We find that the average rotational speed of the turbine increases when the turbine is placed in high turbulence by experiments and theory. The hot-wire velocimetry and particle image velocimetry reveal that vortex shedding is mitigated in turbulence, resulting in a reduction of kinetic energy loss into wake.

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Photo by Mark König on Unsplash

Photo by Mark König on Unsplash

Why is it important?

Turbulence has traditionally been viewed as detrimental to wind turbines, as it can cause fatigue fractures and lead to unstable power generation. However, this study reveals that turbulence does not consistently hinder the performance of Savonius turbines, challenging the notion of turbulence as a universal obstacle.

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