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Forced flow response analysis of a turbulent swirling annular jet flame

Douglas, CM and Emerson, BL and Hemchandra, S and Lieuwen, TC (2021) Forced flow response analysis of a turbulent swirling annular jet flame. In: Physics of Fluids, 33 (8).

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Official URL: https://doi.org/10.1063/5.0061053


This study of an externally forced, amplifier-type turbulent reacting swirling annular jet presents a low-order model for the flow response to transverse acoustic excitation and compares the model's predictions with experimental measurements. The model is formulated based on linear stability calculations about the turbulent mean flow and eddy viscosity fields obtained from separate measurements of the unforced flow. The stability calculations yield weakly global spatial modes associated with the forcing frequency, which serve as a basis upon which to project the forcing input. Thus, the model constitutes a hydrodynamic transfer function connecting the input forcing to the output coherent flow response through the linearized low Mach number compressible Navier-Stokes equations. Following a detailed presentation of the stability analysis underlying the model, the response predictions are evaluated against previously reported experiments where the jet was transversely excited at both an acoustic pressure node and an antinode. The results reveal excellent agreement between the predicted response and the measured fluctuating fields, suggesting that the low-order linear model based on the turbulent mean flow field captures the essential physics of the mode selection process in this forced configuration. This work provides further evidence that linear hydrodynamics govern the growth and decay of spatiotemporally coherent vortical structures in the swirling, turbulent jet flame, and, in particular, explains the dominance of co-rotating spiral structures. © 2021 Author(s).

Item Type: Journal Article
Publication: Physics of Fluids
Publisher: American Institute of Physics Inc.
Additional Information: The copyright for this article belongs to Authors
Keywords: Hydrodynamics; Mach number, Acoustic excitation; Compressible Navier-Stokes equations; Forcing frequencies; Linear hydrodynamics; Response prediction; Stability calculation; Turbulent jet flames; Vortical structures, Navier Stokes equations
Department/Centre: Division of Mechanical Sciences > Aerospace Engineering(Formerly Aeronautical Engineering)
Date Deposited: 02 Dec 2021 13:02
Last Modified: 02 Dec 2021 13:02
URI: http://eprints.iisc.ac.in/id/eprint/70092

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