Secondary instability in variable-density round jets

Abstract : Side jet formation in variable-density round jets is investigated by means of direct numerical simulation (DNS) and linear stability analysis. From DNS, it is observed that a light jet with density ratio S = rho(0)/rho(j) = 4 supports sustained side jets which eject fluid from the center of the jet in a star-shaped pattern. These side jets persist over an axial distance of approximately 5 jet diameters before the jet transitions to turbulence, and do not precess around the jet. It is conjectured that this behavior can be explained by a change in the local properties of the secondary instability from convective to absolute in nature. This hypothesis is tested by examining the spatio-temporal development of the wavepacket resulting from a small impulse, taken about a non-diffusing periodic base state corresponding to the saturated primary instability.
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Communication dans un congrès
J.M.L.M. Palma, A. Silva Lopes. 11th EUROMECH European Turbulance Conference, Jun 2007, Porto, Portugal. Springer, 117, pp.32-34, 2007, Springer Proceedings Physics. 〈10.1007/978-3-540-72604-3_9〉
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https://hal-polytechnique.archives-ouvertes.fr/hal-01026018
Contributeur : Denis Roura <>
Soumis le : lundi 21 juillet 2014 - 14:19:26
Dernière modification le : jeudi 11 janvier 2018 - 06:18:25

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Joseph W. Nichols, Jean-Marc Chomaz, Peter J. Schmid. Secondary instability in variable-density round jets. J.M.L.M. Palma, A. Silva Lopes. 11th EUROMECH European Turbulance Conference, Jun 2007, Porto, Portugal. Springer, 117, pp.32-34, 2007, Springer Proceedings Physics. 〈10.1007/978-3-540-72604-3_9〉. 〈hal-01026018〉

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