Turbulence measurements in an axisymmetric buoyant plume

An experimental investigation of the velocity and temperature fields in an axisymmetric turbulent buoyant plume is described. The plume source was a heated air jet with an exit densimetric Froude number of 1.4. Measurements were carried out with two-wire probes. One wire was maintained at a constant temperature and the other wire was operated as a resistance thermometer. The outputs from both wires were sampled digitally by an A D converter and the temperature and velocity were computed from the experimentally determined calibration curves. The mean temperature and velocity profiles are presented and compared with previous results obtained by Yih [17]. The profiles of the RMS fluctuating velocity and temperature are also presented along with the velocity-temperature correlations and joint probability distributions. All data show satisfactory agreement with the expected similarity scaling, although there is some evidence in the data for the fluctuating quantities that the plume had not reached a fully developed state.