The effect of distance in flow induced vibration on power conversion caused by the oscillations of two tandem cylinders

Flow-induced vibrations (FIVs) are a type of vibration that is caused by the interaction of a structure with a fluid flow. FIVs can occur in a variety of structures, including bridges, buildings, and offshore structures. In the case of tandem cylinders, FIVs can be caused by the interaction of the two cylinders with the fluid flow.FIVs are suppressed because of their destructive nature. MRElab managed to convert the kinetic energy of water flows into electricity by enhancing FIV (Bernitsas, 2016; Bernitsas et al., 2008). In MRElab, Flow Induced Vibrations (FIV) are studied to convert marine hydrokinetic energy, from oceans, tidal and rivers to electricity using the VIVACE energy harvester. Vortex Induced Vibrations for Aquatic Clean Energy Converter is probably the closest to commercialization because it has suffered extensive laboratory testing and many field deployments since its introduction in 2006. The objective of the Marine Renewable Energy Lab (MRELab) is to investigate FIV of single and multiple cylinders and find different ways to enhance FIV to design VIVACE Converters and optimize the power output for various flow velocities. Vortex-induced vibration (VIV) to a cylinder has been studied experimentally (Alam et al., 2003; Park, 2012) and numerically  (Ding et al., 2013; Kim et al., 2021) by researchers in order to eliminate or at least regulate this unsteady fluid-structure interaction phenomenon since it has been identified as the cause for many structural failures. But it is challenging, and it is still being debated due to the complexity of the interaction between body dynamics and fluid dynamics. The two cylinders arrangement has been studied in many types of research as the simplest arrangement. In this research, both cylinders can oscillate which has not been done very often in previous papers up to now. Moreover, most of the previous experiments on VIV were conducted in TrSL2 regime which fluctuating lift coefficient rises as the Re increases. But in this research, experiments placed in TrSL3 that shear layer becomes fully turbulent, and the fluctuating lift coefficient of a smooth cylinder reaches its maximum value.