Space-Time Correlations of Velocity and Pressure and the Role of Convection for Homogeneous Turbulence in the Universal Range

摘要

Kolmogorov's principles provide a basis for the treatment of Eulerian space-time correlations for turbulence in the universal range by explicit separation of the kinematic effect of convection by the large eddies. With reference to unsheared homogeneous turbulence, the usual similarity forms are assumed for intrinsic velocity correlations in a local co-moving frame. The local-convection approximation, neglecting dispersion in this frame and hence relating space-time correlations to pure spatial correlations, is indicated to be a useful one in the inertial and viscous subranges. For an isotropic normal velocity distribution, the structure functions of fluctuating velocity are computed and found to be nearly space-time isotropic in the former subrange and exactly so in the latter. (Author)