High-resolution measurements of the spatial and temporal scalar structure of a turbulent plume

Two techniques are described for measuring the scalar structure of turbulen t flows. A planar laser-induced fluorescence technique is used to make high ly resolved measurements of scalar spatial structure, and a single-point la ser-induced fluorescence probe is used to make highly resolved measurements of scalar temporal structure. The techniques are used to measure the spati al and temporal structure of an odor plume released from a low-momentum, be d-level source in a turbulent boundary layer. For the experimental setup us ed in this study, a spatial resolution of 150 mum and a temporal resolution of 1,000 Hz are obtained. The results show a wide range of turbulent struc tures in rich detail; the nature of the structure varies significantly in d ifferent regions of the plume.