Time-dependent particle migration and margination in the pressure-driven channel flow of blood

2018 ◽  
Vol 3 (3) ◽  
Author(s):  
Qin M. Qi ◽  
Eric S. G. Shaqfeh
Keyword(s):  
Channel Flow ◽  
Particle Migration ◽  
Time Dependent ◽  
Pressure Driven

Macroscopic Modeling of Viscous Suspension Flows

1994 ◽  
Vol 47 (6S) ◽  
pp. S229-S235 ◽  
Author(s):  
John F. Brady
Keyword(s):  
Shear Flow ◽  
Channel Flow ◽  
Particle Migration ◽  
Balance Model ◽  
Stokesian Dynamics ◽  
Suspension Flows ◽  
Macroscopic Modeling ◽  
Mean Motion ◽  
Dynamics Simulations ◽  
Pressure Driven

Shear-induced particle migration in viscous suspension flows is shown to lead to intrinsic concentration variations in inhomogeneous shear flow. A recently proposed suspension balance model is discussed that explains this migration as resulting from the requirement that the macroscopic suspension pressure be constant perpendicular to the direction of mean motion. The results of this model are shown to compare well with Stokesian Dynamics simulations of pressure-driven channel flow.

scholarly journals Pressure-driven flow of suspensions: simulation and theory

1994 ◽  
Vol 275 ◽  
pp. 157-199 ◽  
Author(s):  
Prabhu R. Nott ◽  
John F. Brady
Keyword(s):  
Particle Velocity ◽  
Particle Migration ◽  
Channel Width ◽  
Stokesian Dynamics ◽  
Dynamic Simulations ◽  
Inhomogeneous Flow ◽  
Pressure Driven Flow ◽  
Energy Balances ◽  
Good Agreement ◽  
Pressure Driven

Dynamic simulations of the pressure-driven flow in a channel of a non-Brownian suspension at zero Reynolds number were conducted using Stokesian Dynamics. The simulations are for a monolayer of identical particles as a function of the dimensionless channel width and the bulk particle concentration. Starting from a homogeneous dispersion, the particles gradually migrate towards the centre of the channel, resulting in an homogeneous concentration profile and a blunting of the particle velocity profile. The time for achieving steady state scales as (H/a)3a/〈u〉, where H is the channel width, a the radii of the particles, and 〈u〉 the average suspension velocity in the channel. The concentration and velocity profiles determined from the simulations are in qualitative agreement with experiment.A model for suspension flow has been proposed in which macroscopic mass, momentum and energy balances are constructed and solved simultaneously. It is shown that the requirement that the suspension pressure be constant in directions perpendicular to the mean motion leads to particle migration and concentration variations in inhomogeneous flow. The concept of the suspension ‘temperature’ – a measure of the particle velocity fluctuations – is introduced in order to provide a nonlocal description of suspension behaviour. The results of this model for channel flow are in good agreement with the simulations.

scholarly journals Rheology and microstructural evolution in pressure-driven flow of a magnetorheological fluid with strong particle–wall interactions

2012 ◽  
Vol 23 (9) ◽  
pp. 969-978 ◽  
Author(s):  
Murat Ocalan ◽  
Gareth H. McKinley
Keyword(s):  
Microfluidic Devices ◽  
Magnetorheological Fluid ◽  
Time Dependent ◽  
Mr Fluid ◽  
Flow Through ◽  
Fluid Particles ◽  
And Performance ◽  
Pressure Driven Flow ◽  
Actuator Design ◽  
Pressure Driven

The interaction between magnetorheological (MR) fluid particles and the walls of the device that retain the field-responsive fluid is critical as this interaction provides the means for coupling the physical device to the field-controllable properties of the fluid. This interaction is often enhanced in actuators by the use of ferromagnetic walls that generate an attractive force on the particles in the field-on state. In this article, the aggregation dynamics of MR fluid particles and the evolution of the microstructure in pressure-driven flow through ferromagnetic channels are studied using custom-fabricated microfluidic devices with ferromagnetic sidewalls. The aggregation of the particles and the time-dependent evolution in the microstructure is studied in rectilinear, expansion and contraction channel geometries. These observations help identify methods for improving MR actuator design and performance.

Particle migration in pressure-driven flow of a Brownian suspension

2003 ◽  
Vol 493 ◽  
pp. 363-378 ◽  
Author(s):  
MARTIN FRANK ◽  
DOUGLAS ANDERSON ◽  
ERIC R. WEEKS ◽  
JEFFREY F. MORRIS
Keyword(s):  
Particle Migration ◽  
Pressure Driven Flow ◽  
Pressure Driven

Dispersion of a buoyant plume in a turbulent pressure-driven channel flow

2009 ◽  
Vol 52 (7-8) ◽  
pp. 1827-1842 ◽  
Author(s):  
Alexandre Fabregat ◽  
Jordi Pallarès ◽  
Ildefonso Cuesta ◽  
Francesc Xavier Grau
Keyword(s):  
Channel Flow ◽  
Buoyant Plume ◽  
Turbulent Pressure ◽  
Pressure Driven

Lagrangian approach to time-dependent laminar dispersion in rectangular conduits. Part 1. Two-dimensional flows

1988 ◽  
Vol 190 ◽  
pp. 201-215 ◽  
Author(s):  
Shimon Haber ◽  
Roberto Mauri
Keyword(s):  
Channel Flow ◽  
Poiseuille Flow ◽  
Open Channel ◽  
Molecular Diffusion ◽  
Dispersion Coefficient ◽  
Brownian Particle ◽  
Open Channel Flow ◽  
Taylor Dispersion ◽  
Time Dependent ◽  
Two Dimensional

Time-dependent mean velocities and dispersion coefficients are evaluated for a general two-dimensional laminar flow. A Lagrangian method is adopted by which a Brownian particle is traced in an artificially restructured velocity field. Asymptotic expressions for short, medium and long periods of time are obtained for Couette flow, plane Poiseuille flow and open-channel flow over an inclined flat surface. A new formula is suggested by which the Taylor dispersion coefficient can be evaluated from purely kinematical considerations. Within an error of less than one percent, over the entire time domain and for various flow fields, a very simple analytical expression is derived for the time-dependent dispersion coefficient \[ \tilde{D}(\tau) = D + D^T\left(1-\frac{1-{\rm e}^{-\alpha\tau}}{a\tau}\right), \] where D is the molecular diffusion coefficient, DT denotes the Taylor dispersion coefficient, τ stands for the non-dimensional time π2Dt/Y/, Y is the distance between walls and a = (N + 1)2 is an integer which is determined by the number of symmetry planes N that the flow field possesses. For Couette and open-channel flow there are no planes of symmetry and a = 1; for Poiseuille flow there is one plane of symmetry and a = 4.

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