Coherent structures: Comments on mechanisms
Abstract
There is now overwhelming evidence that in most turbulent flows there exist regions moving with the flow where the velocity and vorticity have a characteristic structure. These regions are called coherent structures because within them the largescale distributions of velocity and/or vorticity remain coherent even as these structures move through the flow and interact with other structures. Since the flow enters and leaves the bounding surfaces of these structures, a useful definition for coherent structures is that they are open volumes with distinctive largescale vorticity distributions. Possible fruitful directions for the study of the dynamics of coherent structures are suggested. Most coherent structures research to data was concentrated on measurement and kinematical analysis; there is now a welcome move to examine the dynamics of coherent structures, by a variety of different methods. A few of them will be described.
 Publication:

Studying Turbulence Using Numerical Simulation Databases
 Pub Date:
 December 1987
 Bibcode:
 1987stun.proc..315H
 Keywords:

 Computation;
 Homogeneous Turbulence;
 Structural Analysis;
 Turbulent Boundary Layer;
 Turbulent Flow;
 Vortices;
 Flow Distribution;
 Velocity;
 Vorticity;
 Fluid Mechanics and Heat Transfer