Abonnement à la biblothèque: Guest
TSFP DL Home Archives Comité de direction

FLOW AND SOUND FIELDS OF HEATED SUBSONIC TURBULENTJETS

Christophe Bogey
Laboratoire de Mecanique des Fluides et d'Acoustique UMR CNRS 5509, Ecole Centrale de Lyon 69134 Ecully, France

Olivier Marsden
Laboratoire de Mecanique des Fluides et d'Acoustique UMR CNRS 5509, Ecole Centrale de Lyon 69134 Ecully Cedex, France

Résumé

Large-eddy simulations of isothermal and hot round jets have been performed to investigate the influence of temperature on the flow and acoustic fields of initially disturbed high subsonic jets. The jets have an identical velocity yielding a Mach number M = uj/ca = 0.9, diameter-based Reynolds numbers around 105, and temperatures Tj = Ta, Tj = 1.5Ta and Tj = 2.25Ta, where subscripts j and a denote nozzle-exit and ambient conditions, respectively. Very similar exit flow parameters, including 9% of peak turbulence intensity, are also imposed. With increasing temperature, the jets are found to develop more rapidly with higher turbulence levels. The variations of the mixing-layer properties with Tj/Ta are however stronger for jets at a fixed ReD = ujD/Va (and a decreasing Rej = ujD/Vj) than for jets at a constant Rej. As for the sound field, an elevated temperature leads to noisier jets in the former case but quieter jets in the latter. An increase in low-frequency noise is however observed in all cases.