Asymmetric wakes in flows past circular cylinders confined in channels

Abstract

In this paper, we investigate the flow past a circular cylinder confined in a channel at a blockage ratio of β = 0.7 (the ratio of the cylinder diameter and the channel height) for Reynolds numbers between Re = 300 and 3900 using direct numerical simulation (DNS). We show for varying Reynolds numbers a wide range of wake dynamics occur as the spanwise domain length is changed. At a lower Reynolds number of Re = 300, a reverse von Kármán wake alongside either a top- or bottom-biased asymmetry was observed at different spanwise locations. The asymmetry was structurally similar the two-dimensional asymmetry studied by prior investigators, and was found to be a result of the confinement effect. ..