Effect of initial conditions on vortices in a turbulent near wake

A study has been made of turbulent vortices behind various wake generating bodies with the same characteristic dimension h (circular, triangular, and square cylinders and a screen of 50% solidity). Using orthogonal arrays of sixteen X wires, eight in the (x, y) plane and eight in the (x, z) plane, velocity data have been obtained simultaneously in the two planes at x/h=20 and Re (≡U 0 h/ν)=5600. The topology and transport characteristics of the vortices are sensitive to the initial conditions, in particular on whether the wake-generating body is porous or impervious. For the porous body wake, the vortex strength is only about 30-40% of that in the solid body wakes