Full-scale experiments on dispersion around an isolated building using an ionized air tracer technique with very short averaging time

Abstract

Experiments are reported in which negatively ionized air is used as a tracer on the flow and dispersion in the vicinity of an isolated building. The technique permits very rapid response concentration measurements to be made, so that the characteristics of concentration fluctuations can be determined. Experiments have been carried out using both continuous and pulsed ion sources, and with several detectors deployed to reveal aspects of their sequential activation as a puff of ions is carried on a trajectory in the wake region. Statistical aspects of the multi-detector experiments are presented, and suggestions based on these results are put forward concerning further use of the method in examining this type of flow and dispersion behaviour.