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Simulation Numérique et Analyse Physique d'un Jet Propulsif Contrôlé par des Injections Radiales

Abstract : Because of its high temperature, a propulsive jet is a source of infrared radiation which makes combat aircraft vulnerable. However, radiation can be alleviated by an enhancement of the mixing between the jet and the ambient air. This thesis is dedicated to the numerical simulation of a real-life propulsive jet controlled by radial injections and to the physical investigation of the mixing enhancement mechanisms. As for the simulations, RANS and ZDES based upon the Spalart-Allmaras model are used. In the ZDES model, a new mesh cutoff size is proposed and is shown to improve the prediction of the jet near-field. On the whole, the results provided by ZDES are in fair agreement with the mean flow fields of the supersonic jets without and with control, as well for the expansion/compression cells as for the turbulent diffusion. The physical analysis deals with both the compressible and the vortical mechanisms. It is proved that mixing enhancement is only due to the action of vortices. A parametric study gives some information to design an efficient mixer. The analysis of the vortices is focused on the quasi-bidimensional regime of the far-field. Their mean longitudinal evolution is highlighted and the action of the turbulent fluctuations on their decay rate is shown. Finally, two control regimes are identified and respectively associated to a quasi-steady penetration and to an intermittent penetration of the secondary jets.
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https://tel.archives-ouvertes.fr/tel-00218268
Contributor : Nicolas Chauvet <>
Submitted on : Friday, January 25, 2008 - 11:39:17 PM
Last modification on : Friday, October 23, 2020 - 4:52:13 PM
Long-term archiving on: : Thursday, April 29, 2010 - 7:49:17 PM

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  • HAL Id : tel-00218268, version 1

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Nicolas Chauvet. Simulation Numérique et Analyse Physique d'un Jet Propulsif Contrôlé par des Injections Radiales. Dynamique des Fluides [physics.flu-dyn]. Université de Poitiers, 2007. Français. ⟨tel-00218268⟩

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