Viscometric flow under apparent wall slip in parallel-plate geometry

2005 ◽  
Vol 126 (2-3) ◽  
pp. 105-114 ◽  
Author(s):  
O. Wein
Keyword(s):  
Parallel Plate ◽  
Wall Slip ◽  
Viscometric Flow ◽  
Apparent Wall Slip ◽  
Plate Geometry

Anomalous Wall Effects in Parallel Plate Torsional Flow of Highly Concentrated Emulsions

1999 ◽  
Author(s):  
Rajinder Pal
Keyword(s):  
Parallel Plate ◽  
Rheological Behaviour ◽  
Wall Slip ◽  
Nonlinear Behaviour ◽  
Parallel Plates ◽  
Wall Effects ◽  
Water Emulsion ◽  
Highly Nonlinear ◽  
Oil In Water Emulsion ◽  
Plate Geometry

Abstract The rheological behaviour of a highly concentrated oil-in-water emulsion (75.1% by volume oil) was studied employing parallel plate torsional flows, with main emphasis on the wall effects. The steady shear and oscillatory shear data were collected with a controlled stress rheometer using smooth and serrated parallel plate geometries. The effect of the gap-height (between the parallel plates) on the rheological properties was also determined. When a serrated parallel plate geometry is used, the wall (slip) effects are found to be negligible. The data obtained by employing various gap heights overlap with each other. However, in a smooth parallel plate geometry, the emulsion behaviour is strongly affected by slip at the wall. The data obtained by employing various gap heights are different. In the absence of wall effects, the emulsion exhibits a highly nonlinear behaviour characterized by yield stress and high values of storage modulus.

scholarly journals Heuristic derivation of Casimir effect in minimal length theories

2020 ◽  
Vol 29 (02) ◽  
pp. 2050011 ◽  
Author(s):  
Massimo Blasone ◽  
Gaetano Lambiase ◽  
Giuseppe Gaetano Luciano ◽  
Luciano Petruzziello ◽  
Fabio Scardigli
Keyword(s):  
Field Theory ◽  
Parallel Plate ◽  
Casimir Effect ◽  
Generalized Uncertainty Principle ◽  
Casimir Energy ◽  
Minimal Length ◽  
Quadratic Term ◽  
Quantum Field ◽  
The One ◽  
Plate Geometry

We propose a heuristic derivation of Casimir effect in the context of minimal length theories based on a Generalized Uncertainty Principle (GUP). By considering a GUP with only a quadratic term in the momentum, we compute corrections to the standard formula of Casimir energy for the parallel-plate geometry, the sphere and the cylindrical shell. For the first configuration, we show that our result is consistent with the one obtained via more rigorous calculations in Quantum Field Theory (QFT). Experimental developments are finally discussed.

Domain walls inHe3−Ain a parallel-plate geometry

1980 ◽  
Vol 21 (11) ◽  
pp. 5153-5155 ◽  
Author(s):  
Y. R. Lin-Liu ◽  
Kazumi Maki
Keyword(s):  
Parallel Plate ◽  
Domain Walls ◽  
Plate Geometry

Apparent Wall Slip in Capillary Rheometry of Viscoplastic Liquids

2005 ◽  
Author(s):  
Paulo R. Souza Mendes ◽  
Jose´ R. R. Siffert ◽  
Eduardo S. S. Dutra
Keyword(s):  
Shear Stress ◽  
Yield Stress ◽  
Wall Slip ◽  
Momentum Conservation ◽  
Conservation Equation ◽  
Jump Number ◽  
Capillary Rheometry ◽  
Viscosity Function ◽  
Novel Material ◽  
Apparent Wall Slip

We employ a recently proposed viscosity function (Souza Mendes and Dutra, 2004) to analyze the fully developed flow of yield-stress liquids through tubes. We first show that its dimensionless form gives rise to the so-called jump number, a novel material property that measures the shear rate jump that the material undergoes as the yield stress is reached. We integrate numerically the momentum conservation equation that governs this flow together with the generalized Newtonian Liquid model and the above mentioned viscosity function. We obtain velocity and viscosity profiles for the entire range of the jump number. We show that the friction factor f.Re curves display sharp peaks as the shear stress value at the tube wall approaches the yield stress. Finally, we demonstrate the existence of sharp flow rate increases (or apparent slip) as the wall shear stress is increased in the vicinity of the yield stress.

Diffusion-Layer Theory for Flows Under Apparent Wall Slip

1998 ◽  
Vol 63 (1) ◽  
pp. 132-140 ◽  
Author(s):  
Ondřej Wein
Keyword(s):  
Mass Transfer ◽  
Velocity Profile ◽  
Solid Surface ◽  
Diffusion Layer ◽  
Analytical Formula ◽  
Wall Slip ◽  
Slip Effect ◽  
Local Power ◽  
Overall Mass Transfer Coefficient ◽  
Apparent Wall Slip

An explicit analytical formula is given for the overall mass transfer coefficient between the bulk of flowing microdisperse liquid and a small but finite active part of a solid surface. The apparent wall slip effect inside a diffusion layer is reflected through the local power-law velocity profile, vx(z) = Bzp, and a distribution B = B(x,y) over the solid surface.

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