Numerical Analysis of Hydrokinetic Energy Harvesting from Flow-induced Vibration of a Cylinder with a Single Protrusion

Abstract

To better capture current energy based on flow-induced vibration (FIV), a new cylindrical oscillator is proposed in this paper that attaches a single protrusion to a bare cylinder with different shapes (square, triangular, and semi-elliptical) and different circumferential locations (a = 0°, 45°, 90°, 135°, 180°). Two-dimensional (2D) numerical simulations were performed to investigate the vibration characteristics, equilibrium position, wake vortex mode, and energy harvesting characteristics of the cylindrical oscillator over the reduced frequency range of 2 ≤ U*≤ 14. Regarding the protrusion angle, the vibration amplitude of the cylinder was obviously enhanced at a = 45° and 180° but was suppressed at a = 135°. Specifically, the vibration amplitude of the cylinder with the square protrusion can reach up to 3.1D, an increase of 204% compared to that of the bare cylinder. Additionally, as the flow velocity increased, the equilibrium position of the vibrating cylinder at a = 90° had the largest downward offset, reaching a value of -2.42D. The maximum power of 1.33 W was reached for the cylinder with the square protrusion at a = 45°, but at a= 90°, a stable energy recovery bandwidth was achieved. In addition, high energy harvesting efficiency was mainly concentrated on the extremely low flow velocity range, with a maximal efficiency of 9.67%.

Keywords

• flow-induced vibration (fiv)
• energy harvesting
• cylindrical oscillator
• cfd
• passive turbulence control (ptc)