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simulation des grandes echelles de l'ecoulement instationnaire turbulent dans une tuyere 3D transsonique

Abstract : A realistic 3D internal, unsteady, turbulent and compressible ow was simulated using the Large Eddy Simulation (LES). This work was supported by the Consortium Industrie- Recherche en Turbomachines (CIRT) and was conducted in a collaboration with the LEMFI. The selected test-case was a 3D convergent-divergent transsonic nozzle. Indeed there were available experimental results (ONERA) and numerical simulations using RANS approach (LEMFI) that could be used for comparisons with our simulation. Also this configuration contained the main physical phenomena encountered in turbomachinery. The nozzle is a rectangular channel with a swept three-dimensional bump on the lower wall. A 3D shock wave/boundary layer interaction takes place downstream the bump, lea- ding to a large separation. In the LES approach, the large unsteady and energetic scales are calculated. The contri- bution of the unresolved small scales is modeled using the mixed scale model, developped at the LIMSI-CNRS. Time integration of the equations is preformed by a second order explicit Runge-Kutta scheme. The spatial discretization of the Euler fluxes is obtained by a second order TVD Harten-Yee scheme while the viscous fluxes are discretized by a central scheme. The LES of such flow has given some interesting unsteady results. The temporal evolution of the turbulent eddies, convected by the mean flow, has been observed. The large sepa- ration became unstable and the shock wave oscillations were captured by the LES. The methodology was then validated by comparing our results on the isentropic Mach number, the mean velocity and the Reynolds stress tensor to the numerical results given by the statistical modelisation of Launder-Shima (LEMFI) and experiments (ONERA). The kinetic energy balance was also analyzed and compared to the statistical one, in the separation zone. The LES results on the balance of k have shown that this approach pre- dicts correctly the large fluctuations of the pressure in the shock wave measured in the midle of the channel, on the opposite of the statistical ones.
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https://tel.archives-ouvertes.fr/tel-00009629
Contributor : Laure Coquart <>
Submitted on : Thursday, June 30, 2005 - 7:53:30 PM
Last modification on : Thursday, December 10, 2020 - 12:32:13 PM
Long-term archiving on: : Friday, September 14, 2012 - 1:35:10 PM

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  • HAL Id : tel-00009629, version 1

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Laure Coquart. simulation des grandes echelles de l'ecoulement instationnaire turbulent dans une tuyere 3D transsonique. Physique [physics]. Université Pierre et Marie Curie - Paris VI, 2001. Français. ⟨tel-00009629⟩

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