Experimental and Mechanical Measurement of Transverse Deflection and Comparison of Optimal Velocity for Energy Harvesting in Uniform and Tapered Cylinders from Vortex-Induced-Vibrations

Experimental measurements of dynamic instabilities in water environments are challenging due to their fluctuation and small amplitude. Most of studies use electrical circuits, this paper aims to use only mechanical methods to measure vortex induced vibrations. Measuring the fluctuations amplitude can help designing mechanisms for movement and for mechanical energy harvesting. This paper uses the novel particle image velocimetry method. The test comprises of a cylinder moving in water with different velocities. Uniform and tapered cylinders are used. Study of tapered cylinder is unprecedented. Output data is in the form of dimensionless amplitude-velocity graphs. From this test velocity for producing largest amplitude is obtained. It is also seen that in the efficient velocity, amplitude of uniform cylinder is larger. While tapered cylinder is suitable for using in currents with variable velocities.