Flow-induced vibration of a square cylinder and downstream flat plate associated with micro-scale energy harvester

Abstract

The phenomenon of flow-induced vibration (FIV) over a square cylinder at Reynolds numbers, Re = (3.6–12.5 × 103) is numerically studied. This current study provides a detailed explanation of the behaviour of transverse motion of square cylinder with the mass damping ratio, mζ* = 2.48. The computation of FIV is conducted by numerical simulation based on the Unsteady Reynolds Navier-Stokes (URANS) flow field using OpenFOAM software. The first part of the numerical simulation consists of an isolated square cylinder to validate the solution with previous studies. The computation of FIV with a total number of cells, N = 101,662 have shown a comparable pattern of amplitude curve. The coexistence of vortex-induced vibration (VIV) and galloping is observed for a single isolated cylinder. A downstream flat plate is introduced in the second part of the work. Different gaps separation between the cylinder and flat plate (0.1 ⩽G/D ⩽ 3) are simulated. Based on the amplitude curve against reduced velocities 4 ⩽UR⩽ 20, four regimes are identified. According to the power estimation, the optimum gap separation is G/D = 0.1. The harnessed power is higher than a single isolated square cylinder while preserving the robustness for the remote harvesting purpose.