Spacetime correlations
Abstract
The physical interpretation of the various correlations used in turbulence (space correlations, time correlations, spacetime correlations) are indicated, and the experimental procedure is discussed. A gradual approach is made, according to the values of both the mean velocity and the mean velocity gradient with which the turbulence is associated. Homogeneous isotropic turbulence and its laboratory approach by means of grids placed in uniform flows an dealt with, and results for homogeneous anisotropic turbulence are given. Usual turbulent shear flows are discussed. Free edge vicinities are considered, along with the core region of flows in which the turbulent structures organized by mean velocity gradients possessing opposite signs meet. Only Eulerian correlations were considered. A few indications are given for Lagrangian correlations which always have a spacetime nature.
 Publication:

Presented at the VKI Lecture Series 73 on Meas. of Unsteady Fluid Dyn. Phenomena
 Pub Date:
 1975
 Bibcode:
 1975mufd.vkifR..27C
 Keywords:

 Fluid Dynamics;
 SpaceTime Functions;
 Turbulent Flow;
 Unsteady Flow;
 Flow Measurement;
 Flow Velocity;
 Shear Flow;
 Fluid Mechanics and Heat Transfer