Decomposition of Acoustic and Entropy Modes in a Non-Isothermal Gas Affected by a Mass Force

Diagnostics and decomposition of atmospheric disturbances in a planar flow are considered in this work. The study examines a situation in which the stationary equilibrium temperature of a gas may depend on the vertical coordinate due to external forces. The relations connecting perturbations are ana...

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Bibliographic Details
Published in:Archives of acoustics 2018-01, Vol.43 (3), p.497
Main Authors: Leble, Sergey, Perelomova, Anna
Format: Article
Language:English
Subjects:
Acoustics
Decomposition
Energy distribution
Entropy
Perturbation
Online Access:Get full text
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Summary:Diagnostics and decomposition of atmospheric disturbances in a planar flow are considered in this work. The study examines a situation in which the stationary equilibrium temperature of a gas may depend on the vertical coordinate due to external forces. The relations connecting perturbations are analytically established. These perturbations specify acoustic and entropy modes in an arbitrary stratified gas affected by a constant mass force. The diagnostic relations link acoustic and entropy modes, and are independent of time. Hence, they provide an ability to decompose the total vector of perturbations into acoustic and non-acoustic (entropy) parts, and to establish the distribution of energy between the sound and entropy modes, uniquely at any instant. The total energy of a flow is hence determined in its parts which are connected with acoustic and entropy modes. The examples presented in this work consider the equilibrium temperature of a gas, which linearly depends on the vertical coordinate. Individual profiles of acoustic and entropy parts for some impulses are illustrated with plots.
ISSN:0137-5075
2300-262X
DOI:10.24425/123921