scholarly journals Unsteady Flow of a Power-Law Dusty Fluid With Suction

1993 ◽  
Vol 115 (2) ◽  
pp. 330-333 ◽  
Author(s):  
Ali J. Chamkha
Keyword(s):  
Unsteady Flow ◽  
Power Law ◽  
Volume Fraction ◽  
Fluid Phase ◽  
Skin Friction Coefficient ◽  
Implicit Finite Difference Scheme ◽  
Power Law Fluids ◽  
Porous Flat Plate ◽  
Small Volume Fraction ◽  
Implicit Finite Difference

Equations governing flow of a particulate suspension exhibiting finite volume fraction in non-Newtonian power-law fluids are developed and applied to the problem of unsteady flow past an infinite porous flat plate with suction. Numerical results for small volume fraction for the displacement thicknesses for both phases and the skin-friction coefficient for the fluid phase are obtained using an implicit finite difference scheme and presented graphically to elucidate interesting features of the solutions.

Coupling Effects of Viscous Sheet and Ambient Fluid on Boundary Layer Flow and Heat Transfer in Power-Law Fluids

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Xiaochuan Liu ◽  
Liancun Zheng ◽  
Goong Chen ◽  
Lianxi Ma
Keyword(s):  
Heat Transfer ◽  
Power Law ◽  
Numerical Solutions ◽  
Skin Friction Coefficient ◽  
Similarity Solutions ◽  
Temperature Fields ◽  
Ambient Fluid ◽  
Local Skin ◽  
Flow And Heat Transfer ◽  
Power Law Fluids

This paper investigates the flow and heat transfer of power-law fluids over a stretching sheet where the coupling dynamics influence of viscous sheet and ambient fluid is taken into account via the stress balance. A modified Fourier's law is introduced in which the effects of viscous dissipation are taken into account by assuming that the thermal conductivity is to be shear-dependent on the velocity gradient. The conditions for both velocity and thermal boundary layers admitting similarity solutions are found, and numerical solutions are computed by a Bvp4c program. The results show that the viscous sheet and rheological properties of ambient fluids have significantly influences on both velocity and temperature fields characteristics. The formation of sheet varies with the viscosity of fluid and draw ratio, which then strongly affects the relations of the local skin friction coefficient, the local Nusselt number, and the generalized Reynolds number. Moreover, for specified parameters, the flow and heat transfer behaviors are discussed in detail.

scholarly journals Collapse of a neutrally buoyant suspension column: from Newtonian to apparent non-Newtonian flow regimes

2017 ◽  
Vol 826 ◽  
pp. 918-941 ◽  
Author(s):  
A. Bougouin ◽  
L. Lacaze ◽  
T. Bonometti
Keyword(s):  
Power Law ◽  
Temporal Evolution ◽  
Volume Fraction ◽  
Fluid Model ◽  
Particle Diameter ◽  
Shear Thickening ◽  
Shear Thinning ◽  
Rheological Parameters ◽  
Power Law Fluids ◽  
Neutrally Buoyant

Experiments on the collapse of non-colloidal and neutrally buoyant particles suspended in a Newtonian fluid column are presented, in which the initial volume fraction of the suspension $\unicode[STIX]{x1D719}$, the viscosity of the interstitial fluid $\unicode[STIX]{x1D707}_{f}$, the diameter of the particles $d$ and the mixing protocol, i.e. the initial preparation of the suspension, are varied. The temporal evolution of the slumping current highlights two main regimes: (i) an inertial-dominated regime followed by (ii) a viscous-dominated regime. The inertial regime is characterized by a constant-speed slumping which is shown to scale as in the case of a classical inertial dam-break. The viscous-dominated regime is observed as a decreasing-speed phase of the front evolution. Lubrication models for Newtonian and power-law fluids describe most of situations encountered in this regime, which strongly depends on the suspension parameters. The temporal evolution of the propagating front is used to extract the rheological parameters of the fluid models. At the early stages of the viscous-dominated regime, a constant effective shear viscosity, referred to as an apparent Newtonian viscous regime, is found to depend only on $\unicode[STIX]{x1D719}$ and $\unicode[STIX]{x1D707}_{f}$ for each mixing protocol. The obtained values are shown to be well fitted by the Krieger–Dougherty model whose parameters involved, say a critical volume fraction $\unicode[STIX]{x1D719}_{m}$ and the exponent of divergence, depend on the mixing protocol, i.e. the microscale interaction between particles. On a longer time scale which depends on $\unicode[STIX]{x1D719}$, the front evolution is shown to slightly deviate from the apparent Newtonian model. In this apparent non-Newtonian viscous regime, the power-law model, indicating both shear-thinning and shear-thickening behaviours, is shown to be more appropriate to describe the front evolution. The present experiments indicate that the mixing protocol plays a crucial role in the selection of a shear-thinning or shear-thickening type of collapse, while the particle diameter $d$ and volume fraction $\unicode[STIX]{x1D719}$ play a significant role in the shear-thickening case. In all cases, the normalized effective consistency of the power-law fluid model is found to be a unique function of $\unicode[STIX]{x1D719}$. Finally, an apparent viscoplastic regime, characterized by a finite length spreading reached at finite time, is observed at high $\unicode[STIX]{x1D719}$. This regime is mostly observed for volume fractions larger than $\unicode[STIX]{x1D719}_{m}$ and up to a volume fraction $\unicode[STIX]{x1D719}_{M}$ close to the random close packing fraction at which the initial column remains undeformed on opening the gate.

Contribution in Unsteady Flow of Power-Law Fluids

AIAA Journal ◽  
1973 ◽  
Vol 11 (2) ◽  
pp. 238-239 ◽  
Author(s):  
SREEDHAN ROY
Keyword(s):  
Unsteady Flow ◽  
Power Law ◽  
Power Law Fluids

scholarly journals Turbulent Bubble-Laden Channel Flow of Power-Law Fluids: A Direct Numerical Simulation Study

Fluids ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 40
Author(s):  
Felix Bräuer ◽  
Elias Trautner ◽  
Josef Hasslberger ◽  
Paolo Cifani ◽  
Markus Klein
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Power Law ◽  
Volume Fraction ◽  
Vertical Channel ◽  
Shear Thickening ◽  
Volumetric Flow Rate ◽  
Mean Velocity ◽  
Power Law Fluids ◽  
Gas Volume

The influence of non-Newtonian fluid behavior on the flow statistics of turbulent bubble-laden downflow in a vertical channel is investigated. A Direct Numerical Simulation (DNS) study is conducted for power-law fluids with power-law indexes of 0.7 (shear-thinning), 1 (Newtonian) and 1.3 (shear-thickening) in the liquid phase at a gas volume fraction of 6%. The flow is driven downward by a constant volumetric flow rate corresponding to a friction Reynolds number of Reτ≈127.3. The Eötvös number is varied between Eo=0.3125 and Eo=3.75 in order to investigate the influence of quasi-spherical as well as wobbling bubbles and thus the interplay of the bubble deformability with the power-law behavior of the liquid bulk. The resulting first- and second-order fluid statistics, i.e., the gas fraction, mean velocity and velocity fluctuation profiles across the channel, show clear trends in reply to varying power-law indexes. In addition, it was observed that the bubble oscillations increase with decreasing power-law index. In the channel core, the bubbles significantly increase the dissipation rate, which, in contrast to its behavior at the wall, shows similar orders of magnitude for all power-law indexes.

Solution of Unsteady Flow of Power Law Fluids

AIAA Journal ◽  
1972 ◽  
Vol 10 (5) ◽  
pp. 689-691 ◽  
Author(s):  
TOMMY Y.W. CHEN ◽  
DAVID E. WOLLERSHEIM
Keyword(s):  
Unsteady Flow ◽  
Power Law ◽  
Power Law Fluids

Two-dimensional unsteady flow of power-law fluids over a cylinder

2009 ◽  
Vol 64 (12) ◽  
pp. 2978-2999 ◽  
Author(s):  
Vijaya K. Patnana ◽  
Ram P. Bharti ◽  
Raj P. Chhabra
Keyword(s):  
Unsteady Flow ◽  
Power Law ◽  
Two Dimensional ◽  
Power Law Fluids
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