INVESTIGATION OF FLUCTUATING PROPERTIES OF A NEUTRAL PLUME USING DIGITAL IMAGE-ANALYSIS TECHNIQUES

The present paper deals with the technique and the results obtained for the evaluation of fluctuating properties in a neutral plume in turbulent flow using a Digital Image Analysis System for the concentration measurements. The use of optical methods for the concentration measurement in plumes seeded with smoke of other optically reflecting particles is not new, but the application presented here implements a number of improvements which allow to take fact measurements over regions of space covering the full cross-section of the plume. This makes it possible to obtain useful and sufficiently accurate results not only for the mean plume properties but also for the evaluation of the statistics of the associated fluctuations in time and space.