Reynolds-number effects in flow around more-or-less bluff bodies

Abstract

Flow around more or less bluff bodies is determined by flow separation, which mostly is accompanied by the formation of a vortex street. A characterising feature is the unsteadyness of the wake flow caused by the vortex shedding process. Separating flows are very often Reynolds-number dependent, even if the bodies are sharp-edged. The fundamental reason for this dependency are changes in the state of boundary layer and in particular changes in the location of laminar/turbulent transition. A further reason of minor importance are for example variations in the length of separation bubbles. Bodies: circular cylinder, bridge deck sections, airfoil at high angle of attack