DOI: 10.1615/ICHMT.2000.TherSieProcVol2TherSieProcVol1
ISBN Print: 978-961-6353-27-4
SCALAR TRIPLE MOMENTS IN VARIABLE DENSITY TURBULENT JETS: EXPERIMENT AND MODEL
要約
The present paper is concerned with the coupling between the velocity and scalar fields (temperature or gas mass fraction) in variable density turbulent axisymmetric jets both through experimental and numerical approaches. Some results for mixed moments are obtained in the near-field (X/Dj<20) of these jets with a new measurement technique combining hot or cold wire and LDV. A triple moment model based on Deardoff works is developed for the far-field of a helium jet (X/Dj>90). These results are compared with the experimental and numerical study of Panchapakesan and Lumley (1993) in the far-field of a helium jet. The results confirm that the mixing is more efficient and rapid when the density of the central jet is low. Numerical results show that the present model may be improved by taking into account pressure and dissipation terms for predictions of configurations with small density fluctuations. Whatever, for strong density fluctuations some new modelling propositions are needed for better predictions.