Local transport of passive scalar released from a point source in a turbulent boundary layer

Abstract

Simultaneous measurements of streamwise velocity ($\tilde{U}$) and concentration ($\tilde{C}$) for a horizontal plume released at eight different vertical locations within a turbulent boundary layer are discussed in this paper. These are supplemented by limited simultaneous three-component velocity and concentration measurements. Results of the integral time scale ($\unicode[STIX]{x1D70F}_{c}$) of concentration fluctuations across the width of the plume are presented here for the first time. It is found that $\unicode[STIX]{x1D70F}_{c}$ has two distinct peaks: one closer to the plume centreline and the other at a vertical distance of plume half-width above the..