Far-wake characteristics of two-dimensional flow past a normal flat plate

Direct numerical simulation of flow past a normal flat plate having an aspect ratio of 0.125 has been carried out at Reynolds number range of 30–175. The unsteady far-wake observed at low Reynolds number becomes steady for 75⩽Re⩽140. The steady far-wake undergoes a transition at Re=145 with large scale unsteadiness observed in the far-wake. The frequency of the large scale vortex structures, also called secondary vortex structures, is lower than that of the near-wake. At Re=150, the low frequency far-wake vortex street undulates at another frequency, which increases with increasing Reynolds number, resulting in a tertiary vortex pattern. The transitions are found to have no significant effect on the mean integral parameters such as the drag coefficient and the Strouhal number.