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

Abstract

Simultaneous measurements of streamwise velocity (Ũ)and concentration (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 (τn) of concentration fluctuations across the width of the plume are presented here for the first time. It is found that (τn) has two distinct peaks: one closer to the plume centreline and the other at a vertical distance of plume half-width above the centreline. The time-averaged streamwise concentration flux is found to be positive and negative, respe..