Effect of a splitter plate on the performance of magnetostrictive flow-induced vibrational power generator using a cantilevered circular cylinder

Abstract

In order to improve a vibrational power generator using a magnetostrictive material, i.e., Iron-gallium alloy, and flow-induced vibration of a cantilevered cylinder, a fixed splitter plate was installed behind a cantilevered circular cylinder. Effects of a gap between a splitter plate and a circular cylinder on the performance of the response amplitude, the power of the flow-induced vibrational power generator and the vortex shedding frequency were investigated through wind tunnel experiments. Flow visualizations around a circular cylinder were also conducted by a smoke-wire method using a high-speed camera. The test models had a span length L of 200 mm, 300 mm and 400 mm. The diameter of a circular cylinder D of 40 mm. A splitter plate with a length of 400 mm and a thickness of 2 mm was installed behind the center of the model with a gap G varied from 8 to 104 mm. For a small gap ratio of G/D ≤ 0.6, galloping vibration occurred. From the smoke wire visualization, it was related that the upstream flow to the cylinder went along a side surface of the cylinder and the inner circulatory flow was generated near the gap. As a result, the accelerated gap-flow occurred and the negative pressure was generated periodically on the upper or lower side wall of the cylinder. For a large gap ratio of G/D ≥ 1.2, galloping vibration did not occur, and the response amplitude became similar to the circular cylinder without a splitter plate. The power generation of a circular cylinder having L = 200 mm with G/D = 0.2 was largest. However, the onset wind velocity of vibration was larger than that of the other cylinders and gaps.

Keywords

• flow-induced vibration
• circular cylinder
• splitter plate
• vibrational power generator
• energy harvesting
• vortex-induced vibration
• galloping
• smoke-wire method