Noisy Inflows Cause a Shedding-Mode Switching in Flow Past an Oscillating Cylinder

Abstract

Vortex streets formed behind oscillating bluff bodies consist of arrays of groups of two, three, or four vortices classified as $2S$, $P+S$, and $2P$ shedding modes, respectively. The prevailing dominant mode depends primarily on the amplitude and the frequency of the oscillation and on the Reynolds number. We investigate the effect of noise at the inflow on the stability of these vortex modes in laminar flow past a circular cylinder. We employ stochastic simulations based on a new polynomial chaos method to study the shedding-mode switching from a $P+S$ pattern to a $2S$ mode in the presence of noise.