EDUCTION OF COHERENT STRUCTURES IN THE TURBULENT PLANE WAKE.

A new technique is developed for the eduction of large-scale coherent structures in fully-turbulent shear flows without any auxiliary reference signal. The eduction scheme is based on the recognition of large-scale vorticity, i. e. the key coherent structure property itself. With this method, coherent structures are educed in the nearly self-preserving region of the turbulent wake of a circular cylinder at a Reynolds number of 1. 3 multiplied by 10**4. Topological features of the coherent structure and the associated incoherent turbulence characteristics demonstrate the significant role of vortex stretching at the 'saddle' in entrainment, mixing and turbulence production.