Vortex shedding from square prisms in smooth and turbulent flows

Abstract

Visualization and measurements of velocity and pressure were made for the flow past prisms of variable length with square cross-section, placed normal to smooth and turbulent approaching flows. Square prisms shed vortices in one of the two fixed wake planes. The plane of shedding is switched irregularly from one to the other. Flow visualization confirms the two main effects of small– and large-scale turbulence on the flow past square prisms that had previously been suggested. In particular, large-scale turbulence intensifies vortex shedding from square prisms through resonant interaction, thereby reducing the base pressure considerably.