Dynamics of gravitational instability excitation in viscoelastic polytropic fluids

Karmakar, Pralay Kumar; Kalita, Dhrubajit

doi:10.1007/s10509-018-3460-5

Cited by 12 publications

(3 citation statements)

References 19 publications

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“…2 . Viscosity playing as a stabilizing role in self-gravitating systems is a well-known fact established in the literature 37 .…”

Section: Resultsmentioning

confidence: 99%

“…The trends shown by the different coloured lines indicate that an increase in the viscosity gradually decreases the instability growth rate, thereby exhibiting stabilizing influence on the system. This can be physically attributed to the fact that with an increase in the viscosity, the cohesion among fluid layers increases 37 . It means that the interspecies force gets enhanced; thereby, restricting the relative fluid motion.…”

Section: Resultsmentioning

confidence: 99%

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Acoustic stability of a self-gravitating cylinder leading to astrostructure formation

Dasgupta

Atteya

Karmakar

2023

Sci Rep

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We employ a quantum hydrodynamic model to investigate the cylindrical acoustic waves excitable in a gyromagnetoactive self-gravitating viscous cylinder comprised of two-component (electron–ion) plasma. The electronic equation of state incorporates the effect of temperature degeneracy. It reveals an expression for the generalized pressure capable of reproducing a completely degenerate (CD) quantum (Fermi) pressure and a completely non-degenerate (CND) classical (thermal) pressure. A standard cylindrical wave analysis, moderated by the Hankel function, yields a generalized linear (sextic) dispersion relation. The low-frequency analysis is carried out procedurally in four distinct parametric special cases of astronomical importance. It includes the quantum (CD) non-planar (cylindrical), quantum (CD) planar, classical (CND) non-planar (cylindrical), and classical (CND) planar. We examine the multi-parametric influences on the instability dynamics, such as the plasma equilibrium concentration, kinematic viscosity, and so forth. It is found that, in the quantum regime, the concentration plays a major role in the system destabilization. In the classical regime, the plasma temperature plays an important role in both the stabilization and destabilization. It is further seen that the embedded magnetic field influences the instability growth dynamics in different multiparametric regimes extensively, and so forth. The presented analysis can hopefully be applicable to understand the cylindrical acoustic wave dynamics leading actively to the formation of astrophysical gyromagnetic (filamentary) structures in diverse astronomical circumstances in both the classical and quantum regimes of astronomical relevance.

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“…2 . Viscosity playing as a stabilizing role in self-gravitating systems is a well-known fact established in the literature 37 .…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Acoustic stability of a self-gravitating cylinder leading to astrostructure formation

Dasgupta

Atteya

Karmakar

2023

Sci Rep

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“…Recently, Kalita and Karmakar 33 systematically carried out a semianalytic investigation to see the nonlinear evolutionary dynamics of self‐gravitating viscoelastic nonthermal polytropic astrofluid on the Jeansian scales of space and time. Whereas Karmakar and Kalita 34 reported a new generalized viscoelastic fluid model to investigate the gravitational instability in the presence of realistic astronomical relevancy.…”

Section: Introductionmentioning

confidence: 99%

Cross‐diffusion and viscoelastic effects on multidiffusive porous convection

Shivakumara

Rangadhamappa

2020

Heat Trans

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The onset of triply cross-diffusive convection in a viscoelastic fluid-saturated porous layer is investigated as the study is found very relevant for describing natural phenomena (contaminant transport, underground water flow, improved oil recovery, polymer processing).A modified Darcy-Oldroyd-B model is used to describe the viscoelastic fluid flow in a porous medium with full cross-diffusion terms in the diffusivity matrix. A normal mode analysis yields an exact dispersion equation of fifth degree and accordingly the criterion for the onset of stationary and oscillatory convection is obtained. The numerical computations are carried out for diffusivity elements experimentally determined for lysozymesodium chloride-bovine serum albumin (BSA)-water system. Instability is found to occur via oscillatory mode for a certain choice of governing parameters. The relaxation and retardation viscoelastic parameters portray opposing contributions on the oscillatory onset and an increase in the relaxation parameter is to increase the range of retardation parameter up to which the oscillatory convection is preferred. The cross-diffusion is to either delay/hasten the onset of instability based on the magnitude of the stratifying agents. Even minute variations in the cross-diffusion elements indict complete change in the linear instability criteria. The topology of neutral curves disclosed the occurrence of disconnected closed convex oscillatory neutral curve revealing the requirement of three critical solute Darcy-Rayleigh numbers to state fully the instability criteria instead of the usual single value; a novel result ensured from the study. Moreover, the nature of instability for Oldroyd-B, Maxwell and Newtonian fluids turns out to be dissimilar for the same governing parameters. K E Y W O R D Scross-diffusion, disconnected neutral curve, Oldroyd-B fluid, porous media, triple-diffusive convection

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The Jeans instability in viscoelastic spherical astrophysical fluid media

Dasgupta

Karmakar

2019

Astrophys Space Sci

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Dynamics of gravitational instability excitation in viscoelastic polytropic fluids

Cited by 12 publications

References 19 publications

Acoustic stability of a self-gravitating cylinder leading to astrostructure formation

Acoustic stability of a self-gravitating cylinder leading to astrostructure formation

Cross‐diffusion and viscoelastic effects on multidiffusive porous convection

The Jeans instability in viscoelastic spherical astrophysical fluid media

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