Stability of two-layer miscible convection

Wilczynski, Fryderyk; Hughes, David W.

doi:10.1103/physrevfluids.4.103502

Cited by 8 publications

(6 citation statements)

References 34 publications

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“…Therefore, it is inevitable that a gaseous phase will be formed in any realistic natural convection flow. Second, physical phenomena such as the convection in the earth's mantle [70] or engineering applications such as the heat transfer inside magnetic confinement systems in fusion reactors [71] are more accurately modelled as two-layer convection, where the two fluid layers are dynamically coupled.…”

Section: Two-layer Rayleigh-bénard Convectionmentioning

confidence: 99%

FluTAS: A GPU-accelerated finite difference code for multiphase flows

Crialesi-Esposito¹,

Scapin²,

Demou³

et al. 2022

Preprint

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We present the Fluid Transport Accelerated Solver, FluTAS, a scalable GPU code for multiphase flows with thermal effects. The code solves the incompressible Navier-Stokes equation for two-fluid systems, with a direct FFTbased Poisson solver for the pressure equation. The interface between the two fluids is represented with the Volume of Fluid (VoF) method, which is mass conserving and well suited for complex flows thanks to its capacity of handling topological changes. The energy equation is explicitly solved and coupled with the momentum equation through the Boussinesq approximation. The code is conceived in a modular fashion so that different numerical methods can be used independently, the existing routines can be modified, and new ones can be included in a straightforward and sustainable manner. FluTAS is written in modern Fortran and parallelized using hybrid * M.C-E. and N.S. contributed equally to this work.

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Section: Two-layer Rayleigh-bénard Convectionmentioning

confidence: 99%

FluTAS: A GPU-accelerated finite difference code for multiphase flows

Crialesi-Esposito¹,

Scapin²,

Demou³

et al. 2022

Preprint

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“…We characterize the onset of instability and perform an extensive analysis to describe how the behavior of the system varies as a function of plasma parameters and geometrical conguration. The work presented here may therefore be viewed as an extension of our two earlier studies 18,19 . In the former, we restricted our attention solely to the dynamics in the SOL, as well as exploring the analogy between the interchange instability in the plasma edge and that of Rayleigh-Bénard convection.…”

Section: Introductionmentioning

confidence: 67%

“…Recall that varying D n and µ aects Ra * , Pr and Ω according to (21). Thus, variation of µ aects only the diusion term in the vorticity equation (18) and no terms in the density equation (19), whereas variation of D n aects all terms on the right hand side in the vorticity equation, as well as the second and the nal term on the right hand side of the density equation.…”

Section: B Normalizationmentioning

confidence: 99%

Onset of interchange instability in a coupled core–SOL plasma

2020

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The dynamics at the edge of fusion connement devices is driven by interchange instabilities and involves the motion of plasma across two regions the`core region' and the scrape-o layer (SOL), distinguished by whether eld lines are, respectively, closed or connected to the wall. Motivated by this phenomenon, we present an extensive linear stability analysis of a two-layer plasma model encompassing the coupled interactions between the region with closed eld lines and the SOL. We focus on the eect of varying the particle diusivity and ion viscosity, revealing the signicant variation in the spatial structure of the critical modes. In addition, we have investigated the dependence of the stability threshold on the ratio of the width of the region with closed eld lines to that of the SOL; this dependence is strong when the ratio is suciently small, but becomes insignicant once the ratio is of order unity. I.

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“…The onset of convection is described by linearly unstable modes of a stationary state, and is followed by several types of bifurcations of solutions that have been clarified in extensive studies both theoretically and experimentally. However, the assumption of a single fluid does not necessarily hold in real convection phenomena, including the mantle of the Earth [14,17], the plasma inside a nuclear fusion reactor [22], or molten materials in industrial applications [13], where the thermal convection is considered to take place not in a single fluid layer but in two or more layers of different fluids.…”

Section: Introductionmentioning

confidence: 99%

“…In the "viscous coupling" state, the direction of velocity in the upper cell is opposite to that in the cell just below it, while in the "thermal coupling" state, the direction of velocity is the same in the upper cell and the cell just below it. This interesting phenomenon has been studied so far in the framework of linear stability theory by assuming that the interface between the two fluids has an infinitesimal width, but only the viscous coupling convection pattern was obtained [9,22].…”

Section: Introductionmentioning

confidence: 99%

Model system for the transient behavior of double diffusive convection in two miscible layers

Ishikawa

Takehiro

Yamada

2022

Japan J. Indust. Appl. Math.

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We investigate thermal convection in two horizontal layers of miscible fluids with an initial state in which the fluids are at rest and the temperature has a linear continuous vertical distribution, but the concentration takes different constant values in each layer. Because the initial layered state is not a stationary state, most theoretical methods available for immiscible fluids are not applicable to the miscible case. Here we propose a new model of the thermal convection of miscible fluids, which is devised in such a way that the horizontal average of the width of the transitional layer is kept constant. Both the stability of the stationary state in the linear stage and the asymptotic attractors in the nonlinear stage of the model closely describe the transition of the convection pattern in the original system, which is associated with the change of the width of the transitional layer.

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Stability of two-layer miscible convection

Abstract: This is a repository copy of Stability of two-layer miscible convection.

Cited by 8 publications

References 34 publications

FluTAS: A GPU-accelerated finite difference code for multiphase flows

FluTAS: A GPU-accelerated finite difference code for multiphase flows

Onset of interchange instability in a coupled core–SOL plasma

Model system for the transient behavior of double diffusive convection in two miscible layers

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