Maximizing power generation of bi-stable electrostatic energy harvesters in river flow scenarios

Vortex-induced vibrations (VIV) represent a promising mechanism to harvest ambient energy from low-velocity water flows where traditional power generation concepts become excessively bulky or complex. This paper contributes to VIV energy harvesting in a twofold way. On the one hand, we study how bi-stability can be exploited to extend the range of operating conditions (i.e., flow velocities) at which energy can be effectively harvested from VIV. On the other hand, whereas most simulation studies rely on idealized damping-based power take-off systems, we demonstrate the viability of energy extraction from VIV using realistic electrostatic power take-off systems. To achieve these goals, we extend a well-known fully coupled wake–body oscillator model to incorporate the response of a prototypical power take-off and a bi-stable mechanism. We use the model to perform numerical simulations to evaluate and optimize the bi-stable mechanism parameters for target real-world environments, involving stochastic distributions of river flow velocity. Our model can serve as a benchmark to identify ideal performance limits associated with using electrostatic power take-off systems and/or bi-stable mechanisms and perform a comparison with alternative power take-off technologies.