Memory effects in a turbulent plane wake

Abstract

Memory effects in turbulent plane wakes have been investigated for various wake generators (circular, triangular and square cylinders and a screen of 50% solidity) using orthogonal arrays of X-wires, eight in the (x,y) plane and eight in the (x, z) plane. In the far-wake region, discernible differences are observed for different generators, in the measured Reynolds stresses, spectra of v and approximations to the rms spanwise and lateral vorticities. These differences, which reflect variations in various aspects of the organised large-scale structures, are quantified through the contributions these structures make to the Reynolds stresses. The difference between the screen and the solid body wakes is especially pronounced.