Long-wave instability of stratified two-phase MHD flow

Fuente: arXiv
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Main Authors: Parfenov, Arseniy, Gelfgat, Alexander, Brauner, Neima
Format: Preprint
Published: 2025
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author Parfenov, Arseniy
Gelfgat, Alexander
Brauner, Neima
author_facet Parfenov, Arseniy
Gelfgat, Alexander
Brauner, Neima
contents Instability of a stratified two-phase MHD parallel flow between two infinite plates is addressed. We examine the effect of the transverse magnetic field on the base flow and long wave instability of a two-layer system consisting of conductive liquid and non-conductive gas. Both perfectly insulating and perfectly conducting boundaries are considered. To capture the behavior at small but finite wavenumbers, the conventional first-order long-wave stability analysis is extended to higher order terms. Using mercury-air system as a representative test case, the results demonstrate distinct and non-similar base flow and disturbance profiles, as well as different stability maps for insulating versus conducting boundaries. The stability diagrams reveal a non-monotonic influence of the magnetic field on flow stability, showing that, in addition to its expected stabilizing effect, the field can also induce destabilization under certain conditions. Inspection of the disturbance profiles indicates that despite the strong damping of mercury flow by the magnetic field, interaction of the two fluids at the interface and the shear-induced instabilities in the gas layer dominate and can lead to flow destabilization as the magnetic field strength increases.
format Preprint
id arxiv_https___arxiv_org_abs_2508_21489
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Long-wave instability of stratified two-phase MHD flow
Parfenov, Arseniy
Gelfgat, Alexander
Brauner, Neima
Fluid Dynamics
Instability of a stratified two-phase MHD parallel flow between two infinite plates is addressed. We examine the effect of the transverse magnetic field on the base flow and long wave instability of a two-layer system consisting of conductive liquid and non-conductive gas. Both perfectly insulating and perfectly conducting boundaries are considered. To capture the behavior at small but finite wavenumbers, the conventional first-order long-wave stability analysis is extended to higher order terms. Using mercury-air system as a representative test case, the results demonstrate distinct and non-similar base flow and disturbance profiles, as well as different stability maps for insulating versus conducting boundaries. The stability diagrams reveal a non-monotonic influence of the magnetic field on flow stability, showing that, in addition to its expected stabilizing effect, the field can also induce destabilization under certain conditions. Inspection of the disturbance profiles indicates that despite the strong damping of mercury flow by the magnetic field, interaction of the two fluids at the interface and the shear-induced instabilities in the gas layer dominate and can lead to flow destabilization as the magnetic field strength increases.
title Long-wave instability of stratified two-phase MHD flow
topic Fluid Dynamics
url https://arxiv.org/abs/2508.21489