Energy harvesting characteristics of a flapping wing with the oscillating aspirators in uniform flows and shear flows

Abstract

In this study, we install oscillating aspirators on the upper and lower wing surfaces of the airfoil to intensify energy harvesting characteristics of a flapping wing. At the Reynolds number of 1100, an unsteady laminar 2-D numerical simulation has been used to understand the characteristics of flapping wings’ energy harvesting in uniform flows and shear flows. We focus on the adaptability between the oscillating aspirators and the motion of flapping wings, and demonstrate how the oscillating aspirators and its environmental adaptability can help improve energy harvesting efficiency. Under the same working conditions, the energy collection efficiency of flapping wings in shear flows is not as good as that in uniform flows. The results show that when the oscillating aspirator works on lower wing surface at 0.0T–0.5T and works on the upper wing surface at 0.5T–1.0T, the energy collection efficiency reach the highest. The flow field analysis shows that the oscillating aspirator can increase the pressure gap of airfoil’s both sides and makes the vortex closer to the airfoil. The oscillating aspirator can improve the lift force and torque of flapping wings in both uniform flows and linear shear flows.

Keywords

• Flapping wing
• Energy harvesting
• Flow control
• Oscillating aspirators