Turbulent flows, even when stationary on the average, are time-dependent. The study of such flows must take into account their statistical properties, not only spatial but temporal as well. A review is given of the main results of space-time measurements pertaining to: (a) In incompressible flows, double and triple velocity correlations, double correlations of wall pressure and of wall pressure and velocity of the main flow; (b) in compressible flows, double correlations of pressure at the wall and outside supersonic boundary layers, and autocorrelations of velocity in a supersonic wake. The space-time correlations give evidence to the heredity and (a) the convection velocities of the vorticity and entropy modes, as compared to the mean material convection velocity, and (b) the propagation of the acoustical mode.

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