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Title: Large eddy simulations of a transcritical round jet submitted to transverse acoustic modulation

Abstract

This article reports numerical computations of a turbulent round jet of transcritical fluid (low temperature nitrogen injected under high pressure conditions) surrounded by the same fluid at rest under supercritical conditions (high temperature and high pressure) and submitted to transverse acoustic modulations. The numerical framework relies on large eddy simulation in combination with a real-gas description of thermodynamics and transport properties. A stationary acoustic field is obtained by modulating the normal acoustic velocity at the lateral boundaries of the computational domain. This study specifically focuses on the interaction of the jet with the acoustic field to investigate how the round transcritical jet changes its shape and mixes with the surrounding fluid. Different modulation amplitudes and frequencies are used to sweep a range of conditions. When the acoustic field is established in the domain, the jet length is notably reduced and the jet is flattened in the spanwise direction. Two regimes of oscillation are identified: for low Strouhal numbers a large amplitude motion is observed, while for higher Strouhal numbers the jet oscillates with a small amplitude around the injector axis. The minimum length is obtained for a Strouhal number of 0.3 and the jet length increases with increasing Strouhal numbersmore » after reaching this minimum value. The mechanism of spanwise deformation is shown to be linked with dynamical effects resulting from reduction of the pressure in the transverse direction in relation with increased velocities on the two sides of the jet. A propagative wave is then introduced in the domain leading to similar effects on the jet, except that a bending is also observed in the acoustic propagation direction. A kinematic model, combining hydrodynamic and acoustic contributions, is derived in a second stage to represent the motion of the jet centerline. This model captures details of the numerical simulations quite well. These various results can serve to interpret observations made on more complex flow configurations such as coaxial jets or jet flames formed by coaxial injectors.« less

Authors:
 [1]; ; ;  [1]
  1. Laboratoire EM2C, CNRS, CentraleSupélec, Université Paris-Saclay, Grande Voie des Vignes, 92295 Châtenay-Malabry Cedex (France)
Publication Date:
OSTI Identifier:
22598956
Resource Type:
Journal Article
Journal Name:
Physics of Fluids
Additional Journal Information:
Journal Volume: 28; Journal Issue: 5; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1070-6631
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 42 ENGINEERING; AMPLITUDES; BENDING; CALCULATION METHODS; FLUIDS; JETS; LARGE-EDDY SIMULATION; LENGTH; MODULATION; NITROGEN; THERMODYNAMICS; VELOCITY

Citation Formats

Gonzalez-Flesca, M., CNES DLA, 52 Rue Jacques Hillairet, 75612 Paris Cedex, Schmitt, T., Ducruix, S., and Candel, S. Large eddy simulations of a transcritical round jet submitted to transverse acoustic modulation. United States: N. p., 2016. Web. doi:10.1063/1.4948586.
Gonzalez-Flesca, M., CNES DLA, 52 Rue Jacques Hillairet, 75612 Paris Cedex, Schmitt, T., Ducruix, S., & Candel, S. Large eddy simulations of a transcritical round jet submitted to transverse acoustic modulation. United States. https://doi.org/10.1063/1.4948586
Gonzalez-Flesca, M., CNES DLA, 52 Rue Jacques Hillairet, 75612 Paris Cedex, Schmitt, T., Ducruix, S., and Candel, S. 2016. "Large eddy simulations of a transcritical round jet submitted to transverse acoustic modulation". United States. https://doi.org/10.1063/1.4948586.
@article{osti_22598956,
title = {Large eddy simulations of a transcritical round jet submitted to transverse acoustic modulation},
author = {Gonzalez-Flesca, M. and CNES DLA, 52 Rue Jacques Hillairet, 75612 Paris Cedex and Schmitt, T. and Ducruix, S. and Candel, S.},
abstractNote = {This article reports numerical computations of a turbulent round jet of transcritical fluid (low temperature nitrogen injected under high pressure conditions) surrounded by the same fluid at rest under supercritical conditions (high temperature and high pressure) and submitted to transverse acoustic modulations. The numerical framework relies on large eddy simulation in combination with a real-gas description of thermodynamics and transport properties. A stationary acoustic field is obtained by modulating the normal acoustic velocity at the lateral boundaries of the computational domain. This study specifically focuses on the interaction of the jet with the acoustic field to investigate how the round transcritical jet changes its shape and mixes with the surrounding fluid. Different modulation amplitudes and frequencies are used to sweep a range of conditions. When the acoustic field is established in the domain, the jet length is notably reduced and the jet is flattened in the spanwise direction. Two regimes of oscillation are identified: for low Strouhal numbers a large amplitude motion is observed, while for higher Strouhal numbers the jet oscillates with a small amplitude around the injector axis. The minimum length is obtained for a Strouhal number of 0.3 and the jet length increases with increasing Strouhal numbers after reaching this minimum value. The mechanism of spanwise deformation is shown to be linked with dynamical effects resulting from reduction of the pressure in the transverse direction in relation with increased velocities on the two sides of the jet. A propagative wave is then introduced in the domain leading to similar effects on the jet, except that a bending is also observed in the acoustic propagation direction. A kinematic model, combining hydrodynamic and acoustic contributions, is derived in a second stage to represent the motion of the jet centerline. This model captures details of the numerical simulations quite well. These various results can serve to interpret observations made on more complex flow configurations such as coaxial jets or jet flames formed by coaxial injectors.},
doi = {10.1063/1.4948586},
url = {https://www.osti.gov/biblio/22598956}, journal = {Physics of Fluids},
issn = {1070-6631},
number = 5,
volume = 28,
place = {United States},
year = {Sun May 15 00:00:00 EDT 2016},
month = {Sun May 15 00:00:00 EDT 2016}
}