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PhD Defense : Romain BIOLCHINI – Study of temperature effects on subsonic jet noise by Large Eddy Simulation

  Mardi 12 décembre 2017 à 10h30

  Thèses Cerfacs       Cerfacs, Salle de conférence Jean-Claude ANDRÉ    

Abstract

In this PhD thesis, the effects of temperature on aerodynamic development and acoustic radiation of subsonic jets are studied. This is done thanks to 3D compressible Large Eddy Simulations with low dissipative and dispersive numerical schemes that propagate the acoustic waves properly. The far-field noise is then determined with the acoustics analogy proposed by Ffowcs-Williams and Hawkings.First, single round jets are studied. Two operating points are computed: an isothermal jet and a hot jet with an exhaust temperature twice the one of the ambient air (Tj = 2T0). The comparison of both cases is based on a similar exhaust velocity. In both cases, Reynolds number based on the nozzle diameter is above 100 000. To validate numerical methodology, aerodynamic and acoustic results are successfully compared against experiments. Further analyses are conducted to highlight the new acoustic sources that result from the temperature increase and the effects on the azimuthal mode distribution.Secondly, a more complex geometry representative of a real turbofan engine is considered, including two streams and the plug. The same methodology as the one used for the single jet nozzle is applied. Again, two simulations are computed where the exhaust velocities of both streams are kept constant and only the exhaust primary stream temperature is modified (multiplied by two). Differences on aerodynamic development are less important than the ones observed on single stream jets. However, the upstream acoustic radiation is significantly influenced by the modification of the exhaust temperature. In the colder case, upstream acoustic trapped waves are evidenced in the core jet and interact with the plug. This phenomenon is not reproduced when the primary stream is heated and explains the observed differences on the acoustic radiation.

Jury

BAILLY Christophe, Professor, Ecole Centrale de Lyon Advisor
BODARD Guillaume, Engineer, SAFRAN AIRCRAFT ENGINES Invited
CASALIS Grégoire, Professor, ISAE Member
DAVILLER Guillaume, Researcher, CERFACS Co-advisor
FORTUNE Véronique, Associate Professor Pprime Member
JORDAN Peter, Research Fellow Pprime Referee
LAFON Philippe, Research Fellow IMSIA Referee

L'AGENDA

Lundi

09

Décembre

2024

Parallélisme multi-architecture avec la bibliothèque C++/Kokkos

Du lundi 9 décembre 2024 au mercredi 11 décembre 2024

  Formation    

Mardi

21

Janvier

2025

🎓Soutenance de thèse Thomas LESAFFRE

Mardi 21 janvier 2025Du 9h30 à 12h00

  JCA room, CERFACS, Toulouse    

Mercredi

29

Janvier

2025

🎓HDR Omar DOUNIA

Mercredi 29 janvier 2025Du 9h30 à 11h30

  HDR Cerfacs       JCA room, Cerfacs, Toulouse    

CONSULTER L'AGENDA