Modeling of electromechanically coupled beams in axial flow: energy harvesting and piezofluidelastic actuation problems

Abstract

Electromechanically coupled beams in axial flow have been investigated for energy harvesting and also in researches of bio-inspired aquatic robotics. In the first case, the performance of the coupled system in some specific flow regimes is comparable to the performance of horizontal axis wind turbines. In the second case, the piezoelectric actuation of underwater beams results in thrust, and consequently motion, with low power consumption and low noise. The goal of this proposal is the development of a piezofluidelastic model of non-linear beams in axial flow (air or water) for energy harvesting and also for dynamic actuation. An unsteady aero/hydrodynamic model will be combined to a non-linear dynamic model of an electromechanically coupled beam in order to investigate thrust generation and flow energy harvesting. A methodology for the quantification of the energy flow between the structure and the fluid along the length of the body will be presented. This way, one can determine the regions along the body where energy flows from the fluid to the body as well as regions along the body where energy flows from the structure to the fluid, under different flow conditions and structural configurations. This analysis will be then employed to obtain the optimum distribution of piezoelectric sensors for flow energy harvesting from limit cycle oscillations induced by the flow. Moreover, in the dynamic actuation case, the energy flow analysis will provide a better understanding of the propulsion mechanism and ultimately an enhanced actuation voltage to generated thrust ratio. (AU)