Second-order modelling of variable density turbulent jets : evaluation in the near field region

Abstract : This paper is concerned with a complete second-order model of variable density turbulent Jets. Emphasis is given here on the near-fleld region of the flow where it is found that the influence of the density variations is quite important resulting in a complex behaviour of both the mean and turbulent velocity fields. Particular attention has been paid to the mesh grid and the initial conditions so that quantitative comparison with the experimental data obtained in the study developed in parallel to that one at I.M.S.T. can be made. Results relative to the velocity field only will be reported herein since quite few studies have been focusing so far on the near-field region where the model shows shoncomings which may not be visible when looking at results obtained in the far-field where pseudo-similarity is attained.