Abstract:In this paper the issue of the coherent structures of turbulence developing inwallbounded flows is addressed. After a short historical synthesis, some basic concepts arereviewed and the idea of coherent structure is introduced. The phenomena occurring inthe inner and outer regions of the turbulent boundary layer in conjunction withthe most widely used event-detection techniques are considered, with reference to thelarge amount of mainly experimental results existing on the subject. The flow phenomena aredescribed in terms of events occurring in the inner region, large-scale motions developingin the outer layer and dynamics of vortical structures. In the second part of the paper,methods for the eduction of the coherent structures of turbulence from the backgroundflow and results obtained in the framework of each method are presented. The techniquesinvolving the invariants of the velocity gradient tensor, the analysis of the Hessian ofthe pressure and the proper orthogonal decomposition are considered. Each procedure involvesa particular definition of coherent structure that is supported by an appropriatemathematical framework and permits the analysis of a turbulent-flow database in terms ofdynamics of coherent structures. This work may contribute to the dissemination of themost recent concepts and techniques now in use in turbulence research among fluiddynamicists.