scholarly journals Stability of two superposed viscous-viscoelastic fluids

2005 ◽  
Vol 9 (2) ◽  
pp. 87-95 ◽  
Author(s):  
Pardeep Kumar ◽  
Roshan Lal
Keyword(s):  
Dispersion Relation ◽  
Viscous Fluid ◽  
Kinematic Viscosity ◽  
Viscous Fluids ◽  
Stable Case ◽  
Stabilizing Effect ◽  
Unstable Case ◽  
Rayleigh Taylor Instability ◽  
Newtonian Viscous Fluid ◽  
Mode Technique

The Rayleigh-Taylor instability of a Newtonian viscous fluid overlying a Rivlin-Ericksen viscoelastic fluid is considered. Upon application of normal mode technique, the dispersion relation is obtained. As in both Newtonian viscous-viscous fluids the system is stable in the potentially stable case and unstable in the potentially unstable case, this holds for the present problem also. The behavior of growth rates with respect to kinematic viscosity and kinematic viscoelasticity parameters are examined numerically and it is found that both kinematic viscosity and kinematic viscoelasticity have stabilizing effect.

On the Stability of Two Superposed Viscous-Viscoelastic (Walters B′) Fluids

2006 ◽  
Vol 129 (1) ◽  
pp. 116-119 ◽  
Author(s):  
Pardeep Kumar ◽  
Roshan Lal
Keyword(s):  
Viscous Fluid ◽  
Viscoelastic Fluid ◽  
Kinematic Viscosity ◽  
Taylor Instability ◽  
Stable Configuration ◽  
Stabilizing Effect ◽  
Unstable Configuration ◽  
Rayleigh Taylor Instability ◽  
Newtonian Viscous Fluid ◽  
The Stability

The Rayleigh-Taylor instability of a Newtonian viscous fluid overlying Walters B′ viscoelastic fluid is considered. For the stable configuration, the system is found to be stable or unstable under certain conditions. However, the system is found to be unstable for the potentially unstable configuration. Further it is found numerically that kinematic viscosity has a destabilizing effect, whereas kinematic viscoelasticity has a stabilizing effect on the system.

scholarly journals Hydrodynamic and Hydromagnetic Stability of Viscous-Viscoelastic Superposed Fluids in Presence of Suspended Particles

2007 ◽  
Vol 2007 ◽  
pp. 1-6 ◽  
Author(s):  
Pardeep Kumar ◽  
Mahinder Singh
Keyword(s):  
Magnetic Field ◽  
Suspended Particles ◽  
Viscous Fluids ◽  
Horizontal Magnetic Field ◽  
Stable Case ◽  
Unstable Case ◽  
Rayleigh Taylor Instability ◽  
Newtonian Viscous Fluid ◽  
Superposed Fluids ◽  
The Magnetic Field

The Rayleigh‐Taylor instability of a Newtonian viscous fluid overlying an Oldroydian viscoelastic fluid containing suspended particles is considered. As in both Newtonian viscous-viscous fluids, the system is stable in the potentially stable case and unstable in the potentially unstable case, this holds for the present problem also. The effect of a variable horizontal magnetic field is also considered. The presence of magnetic field stabilizes a certain wavenumber band, whereas the system is unstable for all wavenumbers in the absence of the magnetic field for the potentially unstable arrangement.

Rayleigh-Taylor Instability of Viscous-Viscoelastic Fluids in Presence of Suspended Particles Through Porous Medium

1996 ◽  
Vol 51 (1-2) ◽  
pp. 17-22 ◽  
Author(s):  
Pardeep Kumar
Keyword(s):  
Magnetic Field ◽  
Porous Medium ◽  
Suspended Particles ◽  
Taylor Instability ◽  
Viscous Fluids ◽  
Wave Number ◽  
Uniform Rotation ◽  
Stable Case ◽  
Unstable Case ◽  
Rayleigh Taylor Instability

Abstract The Rayleigh-Taylor instability of a Newtonian viscous fluid overlying an Oldroydian viscoelastic fluid containing suspended particles in a porous medium is considered. As in both Newtonian viscous-viscous fluids the system is stable in the potentially stable case and unstable in the potentially unstable case, this holds for the present problem also. The effects of a variable horizontal magnetic field and a uniform rotation are also considered. The presence of magnetic field stabilizes a certain wave-number band, whereas the system is unstable for all wave-numbers in the absence of the magnetic field for the potentially unstable configuration. However, the system is stable in the potentially stable case and unstable in the potentially unstable case for highly viscous fluids in the presence of a uniform rotation.

scholarly journals Effect of Horizontal and Vertical Magnetic Fields on Rayleigh?Taylor Instability

1968 ◽  
Vol 21 (6) ◽  
pp. 923 ◽  
Author(s):  
RC Sharma ◽  
KM Srivastava
Keyword(s):  
Magnetic Fields ◽  
General Equation ◽  
Taylor Instability ◽  
Combined Effect ◽  
Physical Situation ◽  
Stable Case ◽  
Unstable Case ◽  
Rayleigh Taylor Instability ◽  
The Stability ◽  
Superposed Fluids

A general equation studying the combined effect of horizontal and vertical magnetic fields on the stability of two superposed fluids has been obtained. The unstable and stable cases at the interface (z = 0) between two uniform fluids, with both the possibilities of real and complex n, have been. separately dealt with. Some new results are obtained. In the unstable case with real n, the perturbations are damped or unstable according as 2(k'-k~L2)_(<X2-<Xl)k is> or < 0 under the physical situation (35). In the stable case, the perturbations are stable or unstable according as 2(k2_k~L2)+(<Xl-<X2)k is > or < 0 under the same physical situation (35). The perturbations become unstable if HIlIH 1- (= L) is large. Both the cases are also discussed with imaginary n.

Thermal Instability in Rivlin-Ericksen Elastico-Viscous Fluids in Hydromagnetics

1997 ◽  
Vol 52 (4) ◽  
pp. 369-371 ◽  
Author(s):  
R. C. Sharma ◽  
P. Kumar
Keyword(s):  
Magnetic Field ◽  
Viscous Fluid ◽  
Newtonian Fluid ◽  
Thermal Instability ◽  
Viscous Fluids ◽  
Sufficient Condition ◽  
Vertical Magnetic Field ◽  
Stationary Convection ◽  
Stabilizing Effect ◽  
The Magnetic Field

Abstract The thermal instability of a layer of Rivlin-Ericksen elastico-viscous fluid acted on by a uniform vertical magnetic field is considered. For stationary convection, a Rivlin-Ericksen elastico-viscous fluid behaves like a Newtonian fluid. The magnetic field has a stabilizing effect. It is found that the presence of a magnetic field introduces oscillatory modes which were non-existent in its absence. The sufficient condition for the non-existence of overstability is also obtained.

scholarly journals A new upper bound for the largest growth rate of linear Rayleigh–Taylor instability

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Changsheng Dou ◽  
Jialiang Wang ◽  
Weiwei Wang
Keyword(s):  
Surface Tension ◽  
Growth Rate ◽  
Upper Bound ◽  
Viscous Fluids ◽  
Instability Condition ◽  
Interface Surface ◽  
Incompressible Viscous Fluids ◽  
Rayleigh Taylor Instability ◽  
Surface Tensor ◽  
Rt Instability

AbstractWe investigate the effect of (interface) surface tensor on the linear Rayleigh–Taylor (RT) instability in stratified incompressible viscous fluids. The existence of linear RT instability solutions with largest growth rate Λ is proved under the instability condition (i.e., the surface tension coefficient ϑ is less than a threshold $\vartheta _{\mathrm{c}}$ ϑ c ) by the modified variational method of PDEs. Moreover, we find a new upper bound for Λ. In particular, we directly observe from the upper bound that Λ decreasingly converges to zero as ϑ goes from zero to the threshold $\vartheta _{\mathrm{c}}$ ϑ c .

NUMERICAL SIMULATION OF 2D LIQUID SLOSHING

2012 ◽  
Vol 04 (02) ◽  
pp. 1250014 ◽  
Author(s):  
LI CAI ◽  
JUN ZHOU ◽  
FENGQI ZHOU ◽  
WENXIAN XIE ◽  
YUFENG NIE
Keyword(s):  
Kinematic Viscosity ◽  
Numerical Experiments ◽  
Viscous Fluids ◽  
Liquid Sloshing ◽  
Ghost Fluid Method ◽  
Weighted Essentially Nonoscillatory ◽  
Level Set Function ◽  
Real Fluid ◽  
Set Function

In this paper, we present an extended ghost fluid method (GFM) for computations of liquid sloshing in incompressible multifluids consisting of inviscid and viscous regions. That is, the sloshing interface between inviscid and viscous fluids is tracked by the zero contour of a level set function and the appropriate sloshing interface conditions are captured by defining ghost fluids that have the velocities and pressure of the real fluid at each point while fixing the density and the kinematic viscosity of the other fluid. Meanwhile, a second order single-fluid solver, the central-weighted-essentially-nonoscillatory(CWENO)-type central-upwind scheme, is developed from our previous works. The high resolution and the nonoscillatory quality of the scheme can be verified by solving several numerical experiments. Nonlinear sloshing inside a pitching partially filled rectangular tank with/without baffles has been investigated.

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