Analysis of turbulent dense jets discharged to quiescent uniform or stratified ambients

Abstract

The analysis of dense jets is of interest with regard to environmental applications, especially in the design and evaluation of submerged, offshore outfalls from desalination plants. In this paper, the governing conservation equations of mass, momentum, energy and salinity, derived in a curvilinear coordinate system, are solved by an explicit finite-difference method. The influence of temperature and salinity on density of the jet and ambient fluid are incorporated using an equation of state. Turbulent shear stress, heat flux, and mass flux terms appearing in the governing equations are evaluated using simple algebraic expressions for the eddy diffusivities that account for effects on mixing of buoyancy and intermittent turbulence near the edge of the jet. The formulation is parabolic in character, allowing the solution to be marched in the stream-wise direction starting with initial distributions of velocity, temperature, salinity, and discharge orientation. Cases investigated are the dense jet discharging vertically, horizontally, and at various angles to the horizontal into quiescent, uniform or stratified ambient. Predictions are compared with available experimental data for a wide range of Froude numbers.