LAGRANGIAN CORRELATIONS AND SCALES IN UNIFORMLY SHEARED TURBULENCE

The present study focuses on the relationship between dispersion and Lagrangian statistics in a flow with uniform shear and with turbulent stresses and scales that are nearly transversely homogeneous but grow exponentially in the streamwise direction. Based on the assumption that the Lagrangian velocity field is self-preserving, an expression is derived for the Lagrangian autocorrelation coefficient in terms of the mean-square particle dispersion. Estimates of the mean-square particle dispersion, obtained from measurements of the mean temperature field downstream of a thin heated line source in uniformly sheared turbulence, are subsequently used to evaluate the Lagrangian autocorrelation coefficient and the corresponding integral scale and microscale. The ratios of the estimated Lagrangian scales and the Eulerian scales measured in a converted frame are found comparable to the estimates of previous investigators in other flows. © 1990 American Institute of Physics.