Experiments on the flow past a circular cylinder at low Reynolds numbers

TLDR

The study investigates the nature of the transition in vortex‑street mode and the differences between flows on either side of it. The authors measured drag on circular cylinders using quartz‑fiber bending over Reynolds 0.5–100, compared the results with existing experimental data and theoretical predictions, and examined the transition in vortex‑street mode. Experimental evidence indicates a transition in the vortex‑street mode around Reynolds 90, likely switching from a wake‑originating street to one originating near the cylinder.

Abstract

Part I describes measurements of the drag on circular cylinders, made by observing the bending of quartz fibres, in a stream with the Reynolds number range 0·5-100. Comparisons are made with other experimental values (which cover only the upper part of this range) and with the various theoretical calculations. Part II advances experimental evidence for there being a transition in the mode of the vortex street in the wake of a cylinder at a Reynolds number around 90. Investigations of the nature of this transition and the differences between the flows on either side of it are described. The interpretation that the change is between a vortex street originating in the wake and one originating in the immediate vicinity of the cylinder is suggested.