Flow-induced vibration of two tandem cylinders in presence of cross-flow thermal buoyancy

The present work numerically investigates the effects of cross-thermal buoyancy on flow-induced vibration (FIV) of elastically mounted heated tandem cylinder in air. The FIV on the heated tandem cylinders is typically present in the industrial applications; motivated by this, we performed a series of FIV simulations of heated tandem cylinders in the presence of thermal buoyancy. We explored the effect of thermal buoyancy, using Richardson numbers, on the FIV and heat transfer of the tandem cylinders. The simulations were performed for laminar unsteady flow at different Richardson numbers and gap ratios of 2 and 4. The elastically mounted heated cylinders were allowed to oscillate in the transverse direction at different reduced velocities and a fixed mass ratio. The effect of the cross-thermal buoyancy on FIV was characterized through flow structures and quantified using oscillation amplitude and heat transfer rate. The results indicate that the flow around the cylinder and the associated oscillation depend strongly on thermal buoyancy. The findings also indicate that the high cross-thermal buoyancy exhibits an increased oscillation amplitude, or galloping, at higher reduced velocities. Our analysis suggests that the change in the thermal buoyancy affects both cylinder oscillation and heat transfer from the cylinder to the fluid.