The Meniscus Instability in Non-Newtonian Negative Squeeze Films

1990 ◽  
Vol 57 (3) ◽  
pp. 769-775 ◽  
Author(s):  
Hideo Koguchi ◽  
Toshio Yada
Keyword(s):  
Free Surface ◽  
Power Law ◽  
Capillary Number ◽  
Water Solution ◽  
Linear Stability Theory ◽  
Power Law Fluid ◽  
Fluid Films ◽  
Theoretical Criterion ◽  
The Relationship ◽  
Good Agreement

This paper treats an instability at the free surface of non-Newtonian (power-law) fluid films between two tilted plates in a negative squeeze motion. The meniscus instability in a fluid with the power-law constitutive equation was analyzed on the basis of the linear stability theory. In the analysis, a capillary number for the power-law fluid was newly defined and the relationship between the capillary number and the criterion for the instability of meniscus was theoretically deduced. In the experiment, a water solution of polyacrylamide (separan) whose viscosity obeys a power-law of the strain rate was used as a sample fluid, the meniscus instability in the fluid was examined by using a VTR and the wavelength of disturbances was measured. The theoretical criterion for the instability was in good agreement with experiments and the capillary number could rearrange well the experimental results for the disturbances.

scholarly journals Free convection flow of power law fluid in a vertical cylinder of finite height

1995 ◽  
Vol 17 (2) ◽  
pp. 34-39
Author(s):  
Nguyen Van Que
Keyword(s):  
Heat Transfer ◽  
Free Convection ◽  
Power Law ◽  
Average Velocity ◽  
Vertical Cylinder ◽  
Convection Flow ◽  
Power Law Fluid ◽  
Free Convection Flow ◽  
Finite Height ◽  
Good Agreement

A numerical solution has been presented for free convection flow of power law fluid in a vertical cylinder of finite height. The average velocity along the channel and the heat transfer have been calculated. Graphs of velocities and temperature are shown. The results show good agreement with analytic one in the asymptotic case.

Free-surface jet flow of a shear-thinning power-law fluid near the channel exit

2014 ◽  
Vol 748 ◽  
pp. 580-617 ◽  
Author(s):  
Roger E. Khayat
Keyword(s):  
Free Surface ◽  
Power Law ◽  
Shear Thinning ◽  
Viscous Sublayer ◽  
Jet Flow ◽  
Power Law Fluid ◽  
Downstream Distance ◽  
Moderate Reynolds Number ◽  
Sublayer Thickness ◽  
Surface Jet

AbstractThe jet flow of a shear-thinning power-law fluid is examined theoretically as it emerges from a channel at moderate Reynolds number. Poiseuille flow conditions are assumed to prevail far upstream from the exit. The problem is solved using the method of matched asymptotic expansions. A similarity solution is obtained in the inner layer near the free surface, with the outer layer extending to the jet centreline. An inner thin viscous sublayer is introduced to smooth out the singularity in viscosity at the free surface, allowing the inner algebraically decaying solutions to be matched smoothly with the solution near the free surface. A Newtonian jet is found to contract more than a shear-thinning jet. While both the inner-layer thickness and the free-surface height are $O(\mathit{Re}^{-1/3})$, and grow with downstream distance, the sublayer thickness is smaller, $O(\mathit{Re}^{-(1+n)/3})$, growing with distance for $n < 0.5$, and decaying for $n > 0.5$. The relaxation downstream distance for the jet is found to grow logarithmically with $\mathit{Re}$.

A Boubaker Polynomials Expansion Scheme for Solving the Flow of Nonlinear Power-Law Fluid in Semi-Solid State

2012 ◽  
Vol 192-193 ◽  
pp. 276-280
Author(s):  
Kai Kun Wang ◽  
Jin Long Fu ◽  
Xin Hui Si
Keyword(s):  
Solid State ◽  
Power Law ◽  
Analytic Solutions ◽  
Power Law Fluid ◽  
Boubaker Polynomials ◽  
Unsteady Stretching Surface ◽  
Semi Solid ◽  
Power Law Index ◽  
Good Agreement ◽  
Expansion Scheme

The problem of an uncompressible power-law fluid has long been the challenge in semi-solid forming area. In this paper, the flow of a power-law fluid film on an unsteady stretching surface is analyzed by the means of Boubaker Polynomials Expansion Scheme (BPES). Analytic solutions were given and compared with the numerical results for some real power-law index and the unsteadiness parameter in wide ranges. The good agreement between them showed BPES could be used effectively to solve the flow of nonlinear power-law fluid in semi-solid state.

scholarly journals Laminar natural convection of non-Newtonian power-law fluid in an eccentric annulus

2019 ◽  
pp. 424-424
Author(s):  
Oussama Benhizia ◽  
Mohamed Bouzit ◽  
Ahmed Dellil
Keyword(s):  
Nusselt Number ◽  
Natural Convection ◽  
Power Law ◽  
Average Nusselt Number ◽  
Two Dimensional ◽  
Power Law Fluid ◽  
Eccentric Annulus ◽  
Nusselt Numbers ◽  
Laminar Natural Convection ◽  
Good Agreement

This work is about studying the natural convection of two-dimensional steady state non-Newtonian power law fluid numerically. The inner cylinder was put eccentrically into the outer one. The cylinders are held at constant temperatures with the inner one heated isothermally at temperature Th and the outer one cooled isothermally at temperature Tc (Th>Tc). The simulations have been taken for the parameters 103?Ra?105, 10?Pr?103, 0.6?n?1.4, 0???0.9 and an inclination angle ? from 0? up to 90?. The average Nusselt numbers for the previous parameters are obtained and discussed numerically. The results revealed that the average Nusselt number has the highest values when n=0.6, Ra=105 at ?=0 which is a signal for the large transfer herein and has the lowest values for n=1.4, Ra=103 at ?=90? which is a signal that the transfer is by conduction more than convection. Furthermore, the increasing of eccentricity causes an increase in the Nusselt number for all the cases. Finally, the best case where we can get the best heat transfer is at ? = 0, ?=0.9 among them all. The results have compared with some precedent works and showed good agreement.

INSTABILITY OF MULTI-LAYERED POWER LAW FLUID FILMS

1988 ◽  
pp. 842-847
Author(s):  
Zhang Rongji ◽  
Tang Yinnan ◽  
Jiang Tiqian
Keyword(s):  
Power Law ◽  
Power Law Fluid ◽  
Fluid Films

scholarly journals Thermal Effects in Power-Law Fluid Film Lubrication of Rolling/Sliding Line Contact

2019 ◽  
Vol 8 (9) ◽  
pp. 277-283
Keyword(s):  
Power Law ◽  
Thermal Effects ◽  
Hydrodynamic Lubrication ◽  
Hydrodynamic Pressure ◽  
Line Contact ◽  
Power Law Fluid ◽  
Temperature Load ◽  
Film Lubrication ◽  
Good Agreement ◽  
Fluid Film Lubrication

Hydrodynamic lubrication of heavily loaded rigid system of non-symmetric roller bearings is studied to investigate the thermal effects in the operating behavior of line contact under isothermal and adiabatic boundaries. The incompressible power law lubricant is here considered and its consistency is taken to change with hydrodynamic pressure and the corresponding mean lubricant temperature. The flow controlling equations such as momentum, continuity and thermal energy are solved numerically using R-K Fehlberg method. The results obtained particularly, pressure, mean temperature, load and traction profiles are in good agreement with the previous findings.

Withdrawal of power law fluid films

1970 ◽  
Vol 25 (10) ◽  
pp. 1579-1585 ◽  
Author(s):  
P. Groenveld
Keyword(s):  
Power Law ◽  
Power Law Fluid ◽  
Fluid Films

Free Convective Heat and Mass Transfer in a Doubly Stratified Porous Medium Saturated with a Power-Law Fluid

2009 ◽  
Vol 36 (6) ◽  
pp. 524-537 ◽  
Author(s):  
P. A. Lakshmi Narayana ◽  
P. V. S. N. Murthy ◽  
P. V. S. S. S. R. Krishna ◽  
Adrian Postelnicu
Keyword(s):  
Mass Transfer ◽  
Porous Medium ◽  
Heat And Mass Transfer ◽  
Convective Heat ◽  
Power Law ◽  
Power Law Fluid
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