Shear dispersion in combined pressure-driven and electro-osmotic flows in a channel with porous walls

2015 ◽  
Vol 137 ◽  
pp. 205-215 ◽  
Author(s):  
Morteza Dejam ◽  
Hassan Hassanzadeh ◽  
Zhangxin Chen
Keyword(s):  
Shear Dispersion ◽  
Porous Walls ◽  
Pressure Driven

Pressure-driven flow in a channel with porous walls

2011 ◽  
Vol 679 ◽  
pp. 77-100 ◽  
Author(s):  
QIANLONG LIU ◽  
ANDREA PROSPERETTI
Keyword(s):  
Reynolds Number ◽  
Porous Medium ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Three Dimensional Flow ◽  
Porous Layers ◽  
Simple Cubic ◽  
Porous Walls ◽  
Pressure Driven Flow ◽  
Pressure Driven

The finite-Reynolds-number three-dimensional flow in a channel bounded by one and two parallel porous walls is studied numerically. The porous medium is modelled by spheres in a simple cubic arrangement. Detailed results on the flow structure and the hydrodynamic forces and couple acting on the sphere layer bounding the porous medium are reported and their dependence on the Reynolds number illustrated. It is shown that, at finite Reynolds numbers, a lift force acts on the spheres, which may be expected to contribute to the mobilization of bottom sediments. The results for the slip velocity at the surface of the porous layers are compared with the phenomenological Beavers–Joseph model. It is found that the values of the slip coefficient for pressure-driven and shear-driven flow are somewhat different, and also depend on the Reynolds number. A modification of the relation is suggested to deal with these features. The Appendix provides an alternative derivation of this modified relation.

Linear stability analysis of pressure-driven flows in channels with porous walls

2008 ◽  
Vol 604 ◽  
pp. 411-445 ◽  
Author(s):  
NILS TILTON ◽  
LUCA CORTELEZZI
Keyword(s):  
Stability Analysis ◽  
Linear Stability ◽  
Channel Flow ◽  
Porous Wall ◽  
Inertial Effects ◽  
Porous Layers ◽  
Wall Permeability ◽  
Porous Walls ◽  
The Stability ◽  
Pressure Driven

We present the three-dimensional linear stability analysis of a pressure-driven, incompressible, fully developed, laminar flow in a channel delimited by rigid, homogeneous, isotropic, porous layers. We consider porous materials of small permeability in which the maximum fluid velocity is small compared to the mean velocity in the channel region and for which inertial effects may be neglected. We analyse the linear stability of symmetric laminar velocity profiles in channels with two identical porous walls as well as skewed laminar velocity profiles in channels with only one porous wall. We solve the fully coupled linear stability problem, arising from the adjacent channel and porous flows, using a spectral collocation technique. We validate our results by recovering the linear stability results of a flow in a channel with impermeable walls as the permeabilities of the porous layers tend to zero. We also verify that our results are consistent with the assumption of negligible inertial effects in the porous regions. We characterize the stability of pressure-driven flows by performing a parametric study in which we vary the permeability, porosity, and height of the porous layers as well as an interface coefficient, τ, associated with the momentum transfer process at the interfaces between the channel and porous regions. We find that very small amounts of wall permeability significantly affect the Orr–Sommerfeld spectrum and can dramatically decrease the stability of the channel flow. Within our assumptions, in channels with two porous walls, permeability destabilizes up to two Orr–Sommerfeld wall modes and introduces two new damped wall modes on the left branch of the spectrum. In channels with only one porous wall, permeability destabilizes up to one wall mode and introduces one new damped wall mode on the left branch of the spectrum. In both cases, permeability also introduces a new class of damped modes associated with the porous regions. The size of the unstable region delimited by the neutral curve grows substantially, and the critical Reynolds number can decrease to only 10% of the corresponding value for a channel flow with impermeable walls. We conclude our study by considering two real materials: foametal and aloxite. We fit the porosity and interface coefficient τ to published data so that the porous materials we model behave like foametal and aloxite, and we compare our results with previously published numerical and experimental results.

Shear dispersion in combined pressure-driven and electro-osmotic flows in a capillary tube with a porous wall

AIChE Journal ◽  
2015 ◽  
Vol 61 (11) ◽  
pp. 3981-3995 ◽  
Author(s):  
Morteza Dejam ◽  
Hassan Hassanzadeh ◽  
Zhangxin Chen
Keyword(s):  
Capillary Tube ◽  
Porous Wall ◽  
Shear Dispersion ◽  
Pressure Driven

Shear Dispersion in a Rough-Walled Fracture

SPE Journal ◽  
2018 ◽  
Vol 23 (05) ◽  
pp. 1669-1688 ◽  
Author(s):  
Morteza Dejam ◽  
Hassan Hassanzadeh ◽  
Zhangxin Chen
Keyword(s):  
Peclet Number ◽  
Dispersion Coefficient ◽  
Coupled System ◽  
Fracture Aperture ◽  
Maximum Height ◽  
Fracture Roughness ◽  
Péclet Number ◽  
Relative Roughness ◽  
Shear Dispersion ◽  
Porous Walls

Summary An expression is analytically presented for the shear dispersion, or Taylor (1953) and Aris (1956) dispersion, of a solute transporting in a coupled system, which consists of a matrix and a rough-walled fracture. To derive a shear-dispersion coefficient in a fracture with rough and porous walls, the continuities of solute concentrations and their fluxes are imposed at the fracture walls. The dispersion coefficient for the coupled system is obtained as a function of the Péclet number and relative roughness, where the latter parameter is defined as the ratio of the maximum height of the roughness to the minimum half-aperture of the fracture. Several models for fracture-roughness geometry, including periodically and randomly shaped roughness models, are applied to study the effect of fracture-aperture variation on dispersion. The dispersion coefficient for all rough-walled fractures identifies three different regions in terms of the degree of relative roughness. The results show that for small values of the relative roughness (0<ε≤0.1), the dispersion coefficient is at maximum for bell-shaped geometry and at minimum for triangular-shaped and randomly shaped geometries. When the relative roughness is within 0.1<ε<10, the dispersion is observed to be at maximum for rectangular-walled and at minimum for triangular-walled fractures. The results also reveal that for high values of the relative roughness (ε≥10), the dispersion is higher for bell-shaped roughness, whereas the triangular-walled fracture results in the lowest dispersion. It is found that for all roughness geometries an increase in either the Péclet number or relative roughness leads to an increase in the dispersion.

Shear dispersion in a fracture with porous walls

2014 ◽  
Vol 74 ◽  
pp. 14-25 ◽  
Author(s):  
Morteza Dejam ◽  
Hassan Hassanzadeh ◽  
Zhangxin Chen
Keyword(s):  
Shear Dispersion ◽  
Porous Walls

Use of Flexible Materials with a Novel Pressure Driven Equibiaxial Cell Stretching Device for Mechanical Stimulation of Single Mammalian Cells

2003 ◽  
Vol 773 ◽  
Author(s):  
James D. Kubicek ◽  
Stephanie Brelsford ◽  
Philip R. LeDuc
Keyword(s):  
Cell Fate ◽  
Mechanical Stimulation ◽  
Mammalian Cells ◽  
Cellular Response ◽  
Single Cells ◽  
Complex Nature ◽  
Cellular Behavior ◽  
Cell Stretching ◽  
Stimulation Of ◽  
Pressure Driven

AbstractMechanical stimulation of single cells has been shown to affect cellular behavior from the molecular scale to ultimate cell fate including apoptosis and proliferation. In this, the ability to control the spatiotemporal application of force on cells through their extracellular matrix connections is critical to understand the cellular response of mechanotransduction. Here, we develop and utilize a novel pressure-driven equibiaxial cell stretching device (PECS) combined with an elastomeric material to control specifically the mechanical stimulation on single cells. Cells were cultured on silicone membranes coated with molecular matrices and then a uniform pressure was introduced to the opposite surface of the membrane to stretch single cells equibiaxially. This allowed us to apply mechanical deformation to investigate the complex nature of cell shape and structure. These results will enhance our knowledge of cellular and molecular function as well as provide insights into fields including biomechanics, tissue engineering, and drug discovery.

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