Abstract

In this work, experimental results of the study of an axisymmetric turbulent thermal plume rising from a heated disk (500°C) are presented. The phenomenon is governed by the Navier-Stokes equations, where the approximation of Boussinesque is often supposed to be valid. Mean and fluctuating temperature fields with a fine thermocouple, as well as the eventual presence of thermal stratification, have been explored. The evolution of the axial temperature follows the -5/3 law, allowing identification of a self-preservation zone. Using the transverse expansion of the plume (b) the following were determined: (i) traverse spread rate (db/dz=0.136) which agreed with those obtained by other workers, (ii) the position of the virtual origin of the heated source (zo=4.4 cm); and (iii) a similarity variable (b/z) which permitted better representation of a self-preservation situation.