19th Australasian fluid mechanics conference: Flow-induced structural instabilities via spring-mounted lifting flexible plates in a uniform flow for energy harvesting

Abstract

In this paper, two mounting systems are studied and compared. The first is a new system in fluid-structure interaction (FSI) wherein a cantilevered thin flexible plate is aligned with a uniform flow with the upstream end of the plate attached to a spring-mass system: this allows the entire system to oscillate in a direction perpendicular to that of the flow as a result of the mounting's dynamic interaction with the flow-induced oscillations, or flutter, of the flexible plate; we compare this system to one where the upstream end is hinged with a rotational spring at the mount. While the first system is a fundamental problem in FSI, the study of this variation on classical plate flutter is also motivated by its potential as an energy-harvesting system in which the reciprocating motion of the support system would be tapped for energy production. In this paper we formulate and deploy a hybrid of theoretical and computational models for the fluid-structure systems and map out their linear stability characteristics. The computational model detailed is a fully-implicit solution that is very robust to spatial and temporal discretisation. Compared to a fixed cantilever, the introduction of the dynamic support in both systems is shown to yield lower flutter-onset flow speeds and for the spring-mounted cantilever a reduction of the order of the mode that yields the critical flow speed; these effects would be desirable for energy harvesting applications.