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Etude par simulation numérique directe du rayonnement acoustique de couches de mélange isothermes et anisothermes

Abstract : Sound from a mixing layer flow is computed directly by solving the Navier-Stokes equations on a computational domain which is large enough to have access to the far acoustic field. The tool developed uses Direct Numerical Simulation (DNS) coupled with high-order-accurate methods to provide a good accuracy of the directly computed sound. Two- and three-dimensional simulations of isothermal and non-isothermal mixing layers are performed for various regimes, and particularly for low Mach number flows. Indeed, the temporal approach allows to identify the acoustic radiation from each phase of the mixing layer transition. At first, results from direct computations of sound show that the vortex pairing process generates the largest acoustic radiation, in all cases. Secondly, 3D effects give rise to an overall reduction of the acoustic radiation from the mixing layer. In addition, the combined effects of temperature and compressibility on acoustic radiation (increase/decrease of sound emission for low/high Mach number) are consistent with experimental observations. The DNS data are also used to predict noise emission from the Lighthill's acoustic analogy. The results from the direct computations and the acoustic-analogy predictions are in excellent agreement in all cases. In non-isothermal cases, we show the necessity to account for an additional acoustic source term. The analysis of each source term contribution shows the reversal of trend can be understood in terms of a change of the dominant source term.
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https://tel.archives-ouvertes.fr/tel-00006902
Contributor : Véronique Fortuné <>
Submitted on : Friday, September 17, 2004 - 10:34:41 AM
Last modification on : Monday, October 26, 2020 - 2:12:01 PM
Long-term archiving on: : Thursday, September 13, 2012 - 11:50:45 AM

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  • HAL Id : tel-00006902, version 1

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Véronique Fortuné. Etude par simulation numérique directe du rayonnement acoustique de couches de mélange isothermes et anisothermes. Mécanique [physics.med-ph]. Université de Poitiers, 2000. Français. ⟨tel-00006902⟩

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