Experimental study of spacing ratio effect on multiple cylinders Vortex-Induced Vibration Energy Converter (VIVEC) performance

Votex-Induced Vibration Energy Converter (VIVEC) is one device that utilizes current-energy. VIVEC converts the translational motion up and down from a bluff bodies (such as cylinder) attached to a slider into electrical energy. The release of the vortex that forms around the cylinder when it hit by water at a certain speed causing the cylinder oscillating. Several parameters can improve the performance of VIVEC; one of them is the addition of the number of cylinders or using the multi-cylinders on VIVEC. By using the multi-cylinders system, the distance between the cylinders needs to be considered because the vortex formed from one of the cylinders will affect the frequency of other cylinder oscillations behind it. This experiment used a multi-cylinders VIVEC with 2x2 configuration accompanied by distance variation (L / D = 2,4, and 6) and conducted with a fluid velocity of 0.67 m / s (Re = 50,000) in a towing tank. From this research, it was found that the rear cylinder had a better performance than the front with the peak of average A/D reached 0,739 for the upper-end cylinder in L / D = 2.. The power obtained and the efficiency are relatively decreased as the centre to centre spacing increases.