Effect of Location in a Cylinder Wake on Dynamics of a Flexible Energy Harvesting Plate

Abstract

Flexible plate in the wake of a bluff body may be exploited to harvest energy, for example by attaching piezoelectric sheets on both surfaces of the plate. A computational investigation on flow-induced vibration of a flexible plate in the wake of a cylinder is undertaken to understand the effects of plate location on their vibrations and hence, energy harvesting potential. Based on cylinder diameter D (0.1m), flow at a sub-critical Reynolds number of 10000 was considered in the present study. The fluid-structure interaction was implemented via a closely-coupled partitioned scheme that employs a Scale-Adaptive Simulation (SAS) of the Shear Stress Transport (SST) method to model flow turbulence. A flexible plate was placed at several locations (streamwise: x/D = 0.5, 1.0, 1.5, 2.0; crossflow: y/D = 0, 0.25, 0.5) downstream of the cylinder and their flow-induced response were compiled and analysed. Benchmarking of present model showed good agreement with previous experimental investigations. Results suggest that maximum deflection may be found if flexible plate is placed in the region between cylinder surface and x/D < 1.0. Oscillation of flexible plate placed aty/D = 0.25 shows similar amplitude, if not slightly higher, than if plate is placed at wake centerline. Present findings suggest that energy output may be optimised by positioning flexible energy harvesting plates at favourable locations in the wake region.