Energy harvesting from axial fluid-elastic instabilities of a cylinder

A flexible cylindrical system unstable to flutter oscillations is analysed from the perspective of energy harvesting. In this work we analyse the non-linear reduced order model of a two-degree of freedom system of cylinders modelled with discrete stiffness and damping. The non-linear system of equations is solved in terms of cylinder deflection angles. We seek the flow speed range over which flutter oscillations are stable and correspondingly amenable to energy harvesting. Energy harvesters are modelled as viscous dashpots and the coefficients of damping are parametrised in order to determine combinations that harvest maximum power. We show that for harvesting the maximum possible energy the viscous dashpot should be placed away from the region driving the instability and for this model the optimal location is the fixed end. This result is robust to flow speed variation, action of viscous drag and to variations in cylinder geometry.