scholarly journals Effect of boundary roughness on nonlinear saturation of Rayleigh-Taylor instability in couple-stress fluid

2019 ◽  
Vol 8 (1) ◽  
pp. 39-45
Author(s):  
Vishwanath B. Awati ◽  
Krishna B. Chavaraddi ◽  
Priya M. Gouder
Keyword(s):  
Surface Tension ◽  
Couple Stress ◽  
Numerical Technique ◽  
Taylor Instability ◽  
Couple Stress Fluid ◽  
Nonlinear Saturation ◽  
Roughness Effects ◽  
Two Fluids ◽  
Rayleigh Taylor Instability ◽  
Boundary Roughness

Abstract The boundary roughness effects on nonlinear saturation of Rayleigh-Taylor instability (RTI) in couple-stress fluid have been studied using numerical technique on the basis of stability of interface between two fluids of the system. The resulting fourth order ordinary nonlinear differential equation is solved using Adams-Bashforth predictor and Adams-Moulton corrector techniques numerically. The various surface roughness effects and surface tension effects on nonlinear saturation of RTI of two superposed couple-stress fluid and fluid saturated porous media are well investigated. At the interface, the surface tension acts and finally stability of the problem is discussed in detail.

The Rayleigh–Taylor instability of a viscous liquid layer resting on a plane wall

1990 ◽  
Vol 217 ◽  
pp. 615-638 ◽  
Author(s):  
Lori A. Newhouse ◽  
C. Pozrikidis
Keyword(s):  
Surface Tension ◽  
Liquid Layer ◽  
Viscosity Ratio ◽  
Taylor Instability ◽  
Creeping Flow ◽  
Plane Wall ◽  
Ambient Fluid ◽  
Initial Thickness ◽  
Two Fluids ◽  
Rayleigh Taylor Instability

The nonlinear Rayleigh–Taylor instability of a liquid layer resting on a plane wall below a second liquid of higher density is considered. Under the assumption of creeping flow, the motion is studied as a function of surface tension and the ratio of the viscosities of the two fluids. The flow induced by the deformation of the layer is represented by an interfacial distribution of Green's functions. A Fredholm integral equation of the second kind is derived for the density of the distribution, and is solved by successive iteration. The results show that for small and moderate surface tension, the instability of the layer leads to the formation of a periodic array of viscous plumes which penetrate into the overlying fluid. The morphology of these plumes strongly depends upon the viscosity ratio and surface tension. When the viscosity of the overlying fluid is comparable with or larger than that of the layer, the plumes are composed of a well-defined leading drop on top of a narrow stem. When the viscosity of the overlying fluid is smaller than that of the layer, the plumes take the form of a compact column of rising fluid. The size of the drop leading a plume is roughly proportional to the initial thickness of the layer. When surface tension is sufficiently small, ambient fluid is entrained into the leading drop and circulates in a spiral pattern. Convection currents generated by the rising plumes are visualized with streamline patterns, and the rate of thinning of the remnant layer, as well as the speed of the rising drop or plumes, are discussed.

Effects of surface tension and rotation on the Rayleigh–Taylor instability

2002 ◽  
Vol 4 (8) ◽  
pp. 1464-1470 ◽  
Author(s):  
N. F. El-Ansary ◽  
G. A. Hoshoudy ◽  
A. S. Abd-Elrady ◽  
A. H. A. Ayyad
Keyword(s):  
Surface Tension ◽  
Taylor Instability ◽  
Rayleigh Taylor Instability

scholarly journals Experimental investigation into inertial properties of Rayleigh–Taylor turbulence

1997 ◽  
Vol 15 (1) ◽  
pp. 25-31 ◽  
Author(s):  
Yu.A. Kucherenko ◽  
S.I. Balabin ◽  
R. Cherret ◽  
J.F. Haas
Keyword(s):  
Experimental Investigation ◽  
Kinetic Energy ◽  
Turbulent Mixing ◽  
Average Density ◽  
Taylor Instability ◽  
X Ray ◽  
Two Fluids ◽  
Time Space ◽  
Rayleigh Taylor Instability ◽  
Region Size

An experimental investigation into inertial properties of the developed Rayleigh–Taylor instability with the different initial values of the kinetic energy of turbulence has been performed. The experiments were performed by using two fluids having different densities with density ration n = 3. Fluids were placed in an ampoule. At the unstable stage of motion, the ampoule was moving under an acceleration. At a certain instant of time the acceleration was removed and the ampoule moved under the force of inertia. By means of pulsed X-ray photography, the mixing region size and the time-space distributionof the average density of matter in the turbulent mixing region have been determined at different instants of time. The time-space distributions are compared with those obtained by semiempirical theories of mixing.

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