The thermal and momentum structure of an emerging plume



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An analytical study of the thermal and momentum structure of a compressible, axially symmetric turbulent plume was conducted. Experimental data from the literature and recent remote sensing data were analyzed. A finite- difference numerical technique was used to solve the equations of conservation of mass, momentum, and energy for the axial decay and radial distribution of temperature and velocity. Modifications of the dynamic eddy transfer coefficient given in the literature were used in the solutions. The numerical solutions show good agreement with the literature data and the remote sensing data. The initial exit velocity and temperature ratio were found to be the most significant properties characterizing the variations of temperature and velocity. The axial temperature and velocity were found to decay faster as the temperature ratio is increased and as the initial velocity is decreased. The flat initial radial profiles were found to change gradually to a Gaussian profile, the characteristic radius describing the temperature being greater than that for the velocity distribution. Correlations for the eddy transfer coefficient, the radial temperature and velocity distribution coefficient, and the length of the core regions were obtained. A generalized model for the axial decay of temperature and velocity was proposed consisting of, 1) the core regions, where the exit temperature and velocity along the center line remain unchanged; and 2) the fully developed region where the behavior follows that of Priestly's model. The generalized model differs from Priestly's model by addition of the core region, and agrees well with the literature data. [...]