Double diffusive instability with a constriction

Legare, Sierra; Grace, Andrew; Stastna, Marek

doi:10.1063/5.0135159

Cited by 6 publications

(1 citation statement)

References 46 publications

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“…A more recent study, carried out by Hussein [7] revealed that varying the diffusivity ratio of heat, the different molecular diffusivities affect the scalar fluxes through the system. Meanwhile, Legare et al, [8] applied differential diffusion which allows for novel types of hydrodynamic instability to have finite amplitude manifestations even in millimeter-scale channels in their studies.…”

Section: Introductionmentioning

confidence: 99%

Flow Reversal of Unsteady Oscillatory Flow in Combined Convection Fully Developed Vertical Channel

Nur Asiah

2024

ARNHT

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Numerical simulations of flow and heat transfer in an unsteady oscillatory fully developed combined convection are conducted. The temperature on the right wall varies with sinusoidal rhythm over time within a locked mean temperature, whereas the temperature on the left wall remains constant. Both walls are also considered to be stationary. A numerical solution for the momentum and energy equations obtained using the Runga- Kutta method is used to analyze the effect of periodic oscillation on the velocity and temperature configurations, as well as the progression of heat generations. The combined convection process of heat transfer and its flow pattern in a vertical channel is important in many applications, including environmental, industrial, and engineering. This study is prompted by a problem with the heat transfer process, which is difficult, expensive, and time-consuming. The purpose of this study is to develop a mathematical model, find a numerical solution, and conduct parametric studies on the double-diffusive fully developed vertical channel with unsteady oscillatory flow, as well as to investigate the effect of various parameters on the velocity and temperature profiles. The effect of different dimensional parameters is tested and the flow reversal phenomenon is discussed. The dimensional equations are transformed into non-dimensional equations using the similarity technique. Then, the built-in program dsolve in Maple is used to numerically solve the boundary value problem (BVP). A validation study is conducted on a previously reported problem to confirm the validity of the present calculation. The flow and temperature numerical findings are represented visually. It is found that a large development of flow is caused by the plate temperature oscillation with high amplitude, therefore, the nature of the flow differs from the non-oscillating case.

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Section: Introductionmentioning

confidence: 99%

Flow Reversal of Unsteady Oscillatory Flow in Combined Convection Fully Developed Vertical Channel

Nur Asiah

2024

ARNHT

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Sedimentation in particle-laden flows with and without velocity shear

Yang,

Olsthoorn,

Timmermans

2023

Physics of Fluids

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The vertical transport of sediment from particle-laden flows in marine settings can be enhanced by a settling-driven convective instability. The presence of a horizontal velocity shear can further influence this vertical transport. We conduct numerical simulations to investigate the vertical sediment transport in the presence and absence of shear. We show how this transport is determined by a competition between the growth of the settling-driven convective instability (Rayleigh–Taylor) and the stratified shear instability (Kelvin–Helmholtz). In the absence of shear, the Rayleigh–Taylor instability drives enhanced vertical sediment transport; this effect increases with the Stokes settling velocity of the particles and decreases with the stratification strength. In the presence of shear, there are two regimes of effective settling. When the Kelvin–Helmholtz instability grows rapidly and suppresses the Rayleigh–Taylor instability, the effective settling velocity is significantly reduced. On the other hand, if the Rayleigh–Taylor instability dominates and completely inhibits the Kelvin–Helmholtz instability, the effective settling velocity is enhanced due to the additional energy input by shear. We explore the parameter space of these regimes and interpret their physics.

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Weakly nonlinear instability analysis of triple diffusive convection under internal heat generator and modulated boundaries

Jakhar,

Kumar,

Gupta

2023

Physics of Fluids

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A nonlinear instability analysis of triple diffusive convection under the time-dependent heat and mass transfer boundary conditions in the presence of internal heat source is evaluated in this study. On various physical parameters, the momentary behavior of both Sherwood and Nusselt number profiles is examined. In the geometry, we have considered two parallel infinite horizontal plates acting gravity vertically downward z-direction. By using the weakly nonlinear analysis, the Ginzburg–Landau equation is generated for the rate of heat and mass transport. Here, we have considered the temperature and concentration of two solutes. The temperature and first concentration of the solute at the lower plate are higher than the upper plate, while the second concentration of the solute at the upper plate is higher compared to that of the lower plate. According to the different modulation, we have considered four cases based on the phase angle of the modulations. The convective heat and mass transports are measured as a function of the Nusselt number (Nu) and Sherwood number (Sh1 and Sh2) for both the concentration. From the results, it is found that the first Lewis number increases all the considered profiles, while Ri increases the Nusselt number profile only. The principal discovery elucidated by this article resides in the observation that the internal heat source, subject to modulated boundaries, maintains the convective instability if different solutes are used from both ends.

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Double diffusive instability with a constriction

Cited by 6 publications

References 46 publications

Flow Reversal of Unsteady Oscillatory Flow in Combined Convection Fully Developed Vertical Channel

Flow Reversal of Unsteady Oscillatory Flow in Combined Convection Fully Developed Vertical Channel

Sedimentation in particle-laden flows with and without velocity shear

Weakly nonlinear instability analysis of triple diffusive convection under internal heat generator and modulated boundaries

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