Low-speed experiments on the wake characteristics of flat plates normal to an air stream

Abstract

Experiments on isolated fiat plates perpendicular to the wind are described. It is shown that the effects of aspect ratio on drag, base pressure and flow pattern are small up to A = 10. All of these rectangular plates shed turbulent eddies at particular frequencies; generally there are two shedding frequencies for each plate, one associated with the smaller dimension of the plate, and a lower frequency associated with the larger dimension. Large changes in the shape of low-aspect-ratio plates have very small effects on the aerodynamic characteristics but perforating the plate can eliminate the regular shedding of eddies and reduce the random low-frequency velocity fluctuations.