Double-diffusive two-fluid flow in a slippery channel: A linear stability analysis
TLDR
In this article, the effect of velocity slip at the walls on the linear stability characteristics of two-fluid three-layer channel flow was investigated in the presence of double diffusive (DD) phenomenon.Abstract:
The effect of velocity slip at the walls on the linear stability characteristics of two-fluid three-layer channel flow (the equivalent core-annular configuration in case of pipe) is investigated in the presence of double diffusive (DD) phenomenon. The fluids are miscible and consist of two solute species having different rates of diffusion. The fluids are assumed to be of the same density, but varying viscosity, which depends on the concentration of the solute species. It is found that the flow stabilizes when the less viscous fluid is present in the region adjacent to the slippery channel walls in the single-component (SC) system but becomes unstable at low Reynolds numbers in the presence of DD effect. As the mixed region of the fluids moves towards the channel walls, a new unstable mode (DD mode), distinct from the Tollman Schlichting (TS) mode, arises at Reynolds numbers smaller than the critical Reynolds number for the TS mode. We also found that this mode becomes more prominent when the mixed layer overlaps with the critical layer. It is shown that the slip parameter has nonmonotonic effect on the stability characteristics in this system. Through energy budget analysis, the dual role of slip is explained. The effect of slip is influenced by the location of mixed layer, the log-mobility ratio of the faster diffusing scalar, diffusivity, and the ratio of diffusion coefficients of the two species. Increasing the value of the slip parameter delays the first occurrence of the DD-mode. It is possible to achieve stabilization or destabilization by controlling the various physical parameters in the flow system. In the present study, we suggest an effective and realistic way to control three-layer miscible channel flow with viscosity stratification.read more
Citations
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A two-layer model for buoyant displacement flows in a channel with wall slip
TL;DR: In this article, the authors study theoretically buoyant displacement flows of two generalized Newtonian fluids in a two-dimensional (2D) channel with wall slip, where a pseudo-interface separates two miscible (immiscible) fluids at the limit of negligible molecular diffusion (negligible surface tension).
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Dual stratification effects on double-diffusive convective heat and mass transfer of a sheet-driven micropolar fluid flow
TL;DR: In this paper, the influence of nonlinear thermal radiation, thermophoresis, second order slip and magnetic field on the doubly stratified flow of a non-Newtonian micropolar fluid induced by a stretched sheet along with transport of thermal energy and mass species was analyzed.
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Spatio-temporal instability of two superposed fluids in a channel with boundary slip
TL;DR: In this article, a spatio-temporal analysis of a viscosity and density stratified two-fluid flow in a channel with hydrophobic walls, which experience a finite tangential velocity slip, is considered for a range of parameters for which Squire's theorem is not valid.
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Absolute and convective instabilities in double-diffusive two-fluid flow in a slippery channel
TL;DR: In this paper, the authors considered the spatio-temporal instability of a viscous two-fluid symmetric flow in a horizontal slippery channel and showed that it is possible to achieve early transition to turbulence by making the channel walls hydrophobic/rough/porous with small permeability, which can be modelled by the Navier-slip condition.
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Mathematical modelling of ciliary propulsion of an electrically-conducting Johnson-Segalman physiological fluid in a channel with slip.
TL;DR: A mathematical model for the cilia-generated propulsion of an electrically-conducting viscoelastic physiological fluid in a ciliated channel under the action of magnetic field is discussed.
References
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Book
Molecular Gas Dynamics and the Direct Simulation of Gas Flows
TL;DR: The direct simulation Monte Carlo (or DSMC) method has, in recent years, become widely used in engineering and scientific studies of gas flows that involve low densities or very small physical dimensions as mentioned in this paper.
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Local and global instabilities in spatially developing flows
TL;DR: In this article, a review of recent developments in the hydro- dynamic stability theory of spatially developing flows pertaining to absolute/convective and local/global instability concepts is presented.
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A general boundary condition for liquid flow at solid surfaces
TL;DR: In this paper, the authors present results from molecular dynamics simulations of newtonian liquids under shear which indicate that there exists a general nonlinear relationship between the amount of slip and the local shear rate at a solid surface.
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Apparent fluid slip at hydrophobic microchannel walls
TL;DR: In this article, the velocity profiles of water flowing through 30×300 μm channels were measured to within 450 nm of the micro-channel surface and the measured velocity profiles were consistent with solutions of Stokes' equation and the well accepted no-slip boundary condition.