رها شدن ناگهاني ترمال طوقه اي با شناوري منفي

Impulsive annular release of a negatively buoyant puff

The aim of this work is to model a rapid, radial release of a known volume of a dense fluid into environments of various conditions. What is reported, here, is a simple situation in which the environment is calm and unstratified, with the released fluid having a density which is the same or greater than the density of the ambient fluid. The impulsive jet grows linearly in size with the distance from the source and forms a toroidal shape cloud, which decelerated as it entrains the surrounding fluid. When the released fluid is denser than ambient, this inertial dominated motion near the source is altered (when F0t = M0 ) and the cloud descends vertically under its own negative buoyancy at some distance from the source. Upon reaching the ground plane, the cloud forms a radially symmetric gravity current, moving away from and, to a lesser extent, towards the source. Quantitative data were extracted from flow visualization results and compared with a mathematical model based on the self-similarity theoiy. The model predications and the laboratory observations, including the velocity and size of the toroidal cloud, were generally consistent Concentration measurements at ground level were also in good agreement with values predicted from the analysis. It was apparent, however, that some aspects of the mathematical modeling were simple and require further consideration.