Memory effects in turbulence
Abstract
It is shown that the effects of a turbulent flow are not strictly local and that memory effects play a significant role, so that momentum exchange processes are not determined by the local gradient of the mean velocity alone. This is demonstrated by experimental investigations of the wake flows of a hemisphere in a turbulent boundary layer and of a cylinder. Both cases involve a rapidly changing flow in the developing region. When the shear stress is expressed by the velocity gradient and a vorticity viscosity, the vorticity viscosity, when corrected for the memory effect, equals the value for the developed flow.
 Publication:

Zeitschrift Angewandte Mathematik und Mechanik
 Pub Date:
 October 1976
 DOI:
 10.1002/zamm.19760561007
 Bibcode:
 1976ZaMM...56..403H
 Keywords:

 Fluid Dynamics;
 Turbulent Boundary Layer;
 Turbulent Flow;
 Turbulent Wakes;
 Vorticity Equations;
 Cylindrical Bodies;
 Integral Equations;
 Shear Stress;
 Turbulence Effects;
 Viscous Flow;
 Fluid Mechanics and Heat Transfer