Nonlinear equation of state effects and the momentumdilution tradeoff in a turbulent buoyant jet
Abstract
This paper presents the results of an investigation aimed at determining the effects of using a nonlinear equation of state (instead of a linearized one) in a mathematical model of an axisymmetric turbulent buoyant jet in a neutrally stratified ambient. It also seeks to establish criteria to determine whether a linear or nonlinear equation of state should be used in the numerical modelling of axisymmetric turbulent buoyant jets in a stagnant neutrally stratified ambient. The fluid flow equations derived for the fully developed flow field of a round turbulent buoyant jet, together with the nonlinear equations of state corresponding to various types of jets (e.g. hot water jets, hot air jets, saline water jets), are solved. The numerical solutions are compared to that of a similar jet model that uses a linearized equation of state in order to arrive at guidelines in using a linearized or nonlinear equation of state. These guidelines involve (1) the fluid medium to be used, (2) the property of the jet that gives rise to the buoyancy (e.g. temperature differences, concentration differences, etc.) and (3) the initial density parameter, d(sub O). The nonlinear equation of state is then applied to a hot water buoyant jet model to see whether the momentumdilution tradeoff observed in fitting the prediction of a hot water jet model using a linearized equation of state to the data would be diminished. Results show that a nonlinear equation of state greatly improves the data fitting process.
 Publication:

NASA STI/Recon Technical Report N
 Pub Date:
 May 1987
 Bibcode:
 1987STIN...8826610P
 Keywords:

 Buoyancy;
 Equations Of State;
 Mathematical Models;
 Nonlinear Equations;
 Turbulent Flow;
 Air Jets;
 Flow Distribution;
 Gas Flow;
 Gas Jets;
 Hydraulic Jets;
 Turbulence;
 Turbulent Jets;
 Fluid Mechanics and Heat Transfer