Probability distributions and correlations in a turbulent boundary layer

Abstract

One-dimensional and joint probability density distributions for longitudinal components of turbulent velocities as well as higher-order correlations are measured in a turbulent boundary layer on a flat plate using hot-wire anemometry and high-speed computing methods. The effect of the nonlinear response of the hot-wire is taken into account. Data pertaining to the general nature of the turbulent boundary layer are presented and comparison is made between the measured correlations and those corresponding to a Gaussian probability distribution of turbulent velocities as well as to non-Gaussian distributions of the Gram-Charlier type. Similar comparisons are made of the measured one-dimensional and joint probability distributions. Probability distributions in the boundary layer are also compared to those measured downstream of a grid. The closure of the tails of the probability distribution and its effect on the accuracy of the measurements of higher-order moments is considered.