The prediction of turbulent jets and plumes by use of the k-W model of turbulence

A buoyancy-extended version of the k-W model of turbulence is presented for calculating the flow in turbulent jets and plumes in uniform or stratified ambients. Differential transport equations are solved for the turbulence kinetic energy, the mean square vorticity fluctuations, and the mean square temperature fluctuations. The model incorporates an algebraic stress closure for the turbulent shear stress, and the cross-stream turbulent heat flux is calculated by means of a prescribed constant value of turbulent Prandtl number. The vertical turbulent heat flux is evaluated by relating this quantity not to the gradients, but to the local values of turbulence kinetic energy and mean square temperature fluctuations. Some additional calculations are reported where the cross-stream turbulent heat flux is calculated from an algebraic heat-flux closure. The turbulence model is applied to the calculation of self-similar jets and plumes, and also to forced plumes in uniform and stratified environments. The results are compared with the available experimental data and are found to be in good agreement with the measurements.