Loss of a fixed plane of symmetry in the wake of a sphere

This paper reports about an experimental investigation of the loss of a fixed plane of symmetry in the wake of a sphere. The symmetry plane appears at the first bifurcation for the Reynolds number Re approximate to 212 and is preserved by a secondary Hopf bifurcation that sets in for Re approximate to 275. Upon increase of the Reynolds number the symmetry plane eventually breaks as a consequence of further transitions. The aim of this work is to look closer at the breaking of the planar symmetry of the wake and to establish its critical Reynolds number using a precise experimental technique. The experiments were carried out in a low velocity horizontal water channel for Reynolds numbers ranging from 270 to 500. (C) 2012 Elsevier Ltd. All rights reserved.