Cross-flow vortex-induced vibrations of a circular cylinder under stochastic inflow at low Reynolds number

The vortex-induced vibrations of an elastically mounted circular cylinder (with mass ratio = 2) in stochastically fluctuating inflow are numerically studied at a Reynolds number of 150. Numerical simulations are carried out on a discrete forcing immersed boundary method (IBM) based in-house fluid–structure interactions (FSI) solver. The existence of gust in the incoming flow causes substantial qualitative and quantitative changes in the vibrating system’s flow and response properties. The oscillation amplitude and extent of lock-in have been found to increase. In the noisy inflow, the vibrating system experiences higher fluid forces than the uniform inflow. A comparison with the vibration characteristics under uniform flow has been conducted to understand the noise’s influence better. Standard vortex-shedding patterns are not detected in the wake. Instead, rich vortex interaction behavior like vortex-merging, vortex-pairing, and formation of mushroom-shaped vortical structures are documented. •Stochastic noise expands the cylinder’s lock-in range.•Noise causes moments of thrust, not just drag.•Noisy flow disrupts traditional wake patterns.•Vortex merging dominates in noisy lock-in zones.•Higher mass ratio shortens lock-in and reduces oscillation amplitude.