Reynolds shear stress and heat flux balance in a turbulent round jet

Measurements are presented of the budgets of the turbulent energy, Reynolds shear stress, and the heat flux in an axisymmetric heated turbulent jet with a coflowing isothermal external stream. The jet-to-external-velocity ratio is 6.6, and the temperature of the jet is 34 C above that of the ambient temperature external stream. The budgets are obtained for both the conventional and turbulent zone averages of the various quantities. The conventional budgets of the Reynolds shear stress and the axial and radial heat flux show that the production of these quantities is balanced effectively by the terms containing the pressure fluctuations. The turbulent zone budget of the shear stress and radial heat flux show enhanced diffusion of these quantities by the radial velocity fluctuations in the outer part of the jet. The measured values that feature in the budgets together with the distributions, obtained by difference, of the pressure-containing terms are used to test some of the assumptions made by Donaldson for calculating turbulent free shear layers.