scholarly journals Particle Settling in a Non-Newtonian Fluid Medium Processed by Using the CEF Model

2018 ◽  
Author(s):  
Şule Celasun
Keyword(s):  
Newtonian Fluid ◽  
Particle Settling ◽  
Fluid Medium

scholarly journals A Hybrid Approach for the Simulation of the Thermal Motion of a Nearly Neutrally Buoyant Nanoparticle in an Incompressible Newtonian Fluid Medium

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
B. Uma ◽  
R. Radhakrishnan ◽  
D. M. Eckmann ◽  
P. S. Ayyaswamy
Keyword(s):  
Newtonian Fluid ◽  
Brownian Particle ◽  
Equations Of Motion ◽  
Hybrid Approach ◽  
Thermal Motion ◽  
Fluctuating Hydrodynamics ◽  
Arbitrary Lagrangian Eulerian ◽  
Fluid Medium ◽  
Incompressible Newtonian Fluid ◽  
Neutrally Buoyant

A hybrid approach consisting of a Markovian fluctuating hydrodynamics of the fluid and a non-Markovian Langevin dynamics with the Ornstein–Uhlenbeck noise perturbing the translational and rotational equations of motion of a nanoparticle is employed to study the thermal motion of a nearly neutrally buoyant nanoparticle in an incompressible Newtonian fluid medium. A direct numerical simulation adopting an arbitrary Lagrangian–Eulerian based finite element method is employed for the simulation of the hybrid approach. The instantaneous flow around the particle and the particle motion are fully resolved. The numerical results show that (a) the calculated temperature of the nearly neutrally buoyant Brownian particle in a quiescent fluid satisfies the equipartition theorem; (b) the translational and rotational decay of the velocity autocorrelation functions result in algebraic tails, over long time; (c) the translational and rotational mean square displacements of the particle obey Stokes–Einstein and Stokes–Einstein–Debye relations, respectively; and (d) the parallel and perpendicular diffusivities of the particle closer to the wall are consistent with the analytical results, where available. The study has important implications for designing nanocarriers for targeted drug delivery. A major advantage of our novel hybrid approach employed in this paper as compared to either the fluctuating hydrodynamics approach or the generalized Langevin approach by itself is that only the hybrid method has been shown to simultaneously preserve both hydrodynamic correlations and equilibrium statistics in the incompressible limit.

scholarly journals Electroosmotic Flow Behavior of Viscoelastic LPTT Fluid in a Microchannel

Micromachines ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 881 ◽  
Author(s):  
Dilin Chen ◽  
Jie Li ◽  
Haiwen Chen ◽  
Lai Zhang ◽  
Hongna Zhang ◽  
...  
Keyword(s):  
Newtonian Fluid ◽  
Electroosmotic Flow ◽  
Fluid Shear Stress ◽  
Viscosity Ratio ◽  
Biological Fluids ◽  
Flow Behavior ◽  
Fluid Velocity ◽  
Viscoelastic Fluids ◽  
Weissenberg Number ◽  
Fluid Medium

In many research works, the fluid medium in electroosmosis is considered to be a Newtonian fluid, while the polymer solutions and biological fluids used in biomedical fields mostly belong to the non-Newtonian category. Based on the finite volume method (FVM), the electroosmotic flow (EOF) of viscoelastic fluids in near-neutral (pH = 7.5) solution considering four ions (K+, Cl−, H+, OH−) is numerically studied, as well as the viscoelastic fluids’ flow characteristics in a microchannel described by the Linear Phan-Thien–Tanner (LPTT) constitutive model under different conditions, including the electrical double layer (EDL) thickness, the Weissenberg number (Wi), the viscosity ratio and the polymer extensibility parameters. When the EDL does not overlap, the velocity profiles for both Newtonian and viscoelastic fluids are plug-like and increase sharply near the charged wall. Compared with Newtonian fluid at Wi = 3, the viscoelastic fluid velocity increases by 5 times and 9 times, respectively, under the EDL conditions of kH = 15 and kH = 250, indicating the shear thinning behavior of LPTT fluid. Shear stress obviously depends on the viscosity ratio and different Wi number conditions. The EOF is also enhanced by the increase (decrease) in polymer extensibility parameters (viscosity ratio). When the extensibility parameters are large, the contribution to velocity is gradually weakened.

Quality of ram spermatozoa separated with modified swim up method

2018 ◽  
Vol 33 (2) ◽  
pp. 62-70 ◽  
Author(s):  
A Hossain ◽  
MM Islam ◽  
F Naznin ◽  
RN Ferdousi ◽  
FY Bari ◽  
...  
Keyword(s):  
Semen Quality ◽  
Membrane Integrity ◽  
Quality Parameters ◽  
Fluid Medium ◽  
Normal Morphology ◽  
The Mean ◽  
Mass Activity ◽  
Fresh Semen ◽  
Artificial Vagina

Semen was collected from four rams, using artificial vagina and viability%, motility% and plasma membrane integrity% were measured. Fresh ejaculates (n = 32) were separated by modified swim-up separation using modified human tubal fluid medium. Four fractions of supernatant were collected at 15-minute intervals. The mean volume, mass activity, concentration, motility%, viability%, normal morphology and membrane integrity% (HOST +ve) of fresh semen were 1.0 ± 0.14, 4.1 ± 0.1 × 109 spermatozoa/ml, 85.0 ± 1.3, 89.4 ± 1.0, 85.5 ± 0.7, 84.7 ± 0.5 respectively. There was no significant (P>0.05) difference in fresh semen quality parameters between rams. The motility%, viability% and HOST +ve % of first, second, third and fourth fractions were 53.4 ± 0.5, 68.2 ± 0.3, 74.8 ± 0.3 and 65.5 ± 0.4; 55.5 ± 0.4, 66.2 ± 0.4, 74.5 ± 0.3 and 73.6 ± 0.3 and 66.7 ± 0.5, 66.8 ± 0.5, 65.2 ± 0.4 and 74.7 ± 0.5 respectively. The motility%, viability% and membrane integrity% of separated semen samples differed significantly (P<0.05) between four fractions. The mean motility% and viability% were significantly higher (P<0.05) in third fraction (74.8 ± 0.3%), whereas the mean HOST +ve% was significantly higher (P<0.05) in fourth fraction (74.7 ± 0.5). All quality parameters of separated spermatozoa were significantly (P<0.05) lower than that of fresh semen. The pregnancy rates were higher with fresh semen (71%) in comparison to that of separated sample (57%).Bangl. vet. 2016. Vol. 33, No. 2, 62-70

An Optimal Homotopy Asymptotic Method Solution of Injection of a Newtonian Fluid Through One Side of a Long Vertical Channel

2011 ◽  
Vol 42 (3) ◽  
pp. 267-283
Author(s):  
Rehan Ali Shah ◽  
Saeed Islam ◽  
A. M. Siddiqui ◽  
Ishtiaq Ali ◽  
Manzoor Ellahi
Keyword(s):  
Newtonian Fluid ◽  
Asymptotic Method ◽  
Vertical Channel ◽  
Optimal Homotopy Asymptotic Method

NUMERICAL MODELING OF NON-NEWTONIAN FLUID FLOW BETWEEN POROUS DISKS IN THE PRESENCE OF NANOPARTICLES

2017 ◽  
Vol 8 (1) ◽  
pp. 67-83
Author(s):  
M. Zubair Akbar Qureshi ◽  
Kashif Ali ◽  
Muhammad Farooq Iqbal ◽  
Muhammad Ashraf
Keyword(s):  
Numerical Modeling ◽  
Fluid Flow ◽  
Newtonian Fluid
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