scholarly journals Flow Pumping by External Periodic Shear Applied to a Soft Interface

2021 ◽  
Author(s):  
Shima Nezamipour ◽  
Ali Najafi
Keyword(s):  
Viscous Fluid ◽  
Capillary Number ◽  
Colloidal Particle ◽  
Optical Tweezer ◽  
Viscous Fluids ◽  
Soft Wall ◽  
Soft Interface

Abstract Flow pumping in viscous fluids is of prime importance in micro-fluidic applications. Here we show that a single colloidal particle in front of a soft wall, manipulated by external means like an optical tweezer, can pump the ambient viscous fluid. The particle, moving back and forth parallel to the soft wall, can produce an averaged net flow in a direction perpendicular to the wall. Using a perturbative scheme, we present the results. Analysis show that this flow in terms of capillary number, scales as Ca2.

scholarly journals Flow pumping by external periodic shear applied to a soft interface

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shima Nezamipour ◽  
Ali Najafi
Keyword(s):  
Viscous Fluid ◽  
Capillary Number ◽  
Colloidal Particle ◽  
Optical Tweezer ◽  
Viscous Fluids ◽  
Soft Wall ◽  
Soft Interface

AbstractFlow pumping in viscous fluids is of prime importance in micro-fluidic applications. Here we show that a single colloidal particle in front of a soft wall, manipulated by external means like an optical tweezer, can pump the ambient viscous fluid. The particle, moving back and forth parallel to the soft wall, can produce an averaged net flow in a direction perpendicular to the wall. Using a perturbative scheme, we present the results. Analysis show that this flow in terms of capillary number, scales as $${\text {Ca}}^2$$ Ca 2 .

Influence of wall roughness on the slip behaviour of viscous fluids

2008 ◽  
Vol 138 (5) ◽  
pp. 957-973 ◽  
Author(s):  
Dorin Bucur ◽  
Eduard Feireisl ◽  
Šárka Nečasová
Keyword(s):  
Boundary Condition ◽  
Viscous Fluid ◽  
Boundary Conditions ◽  
Limit Problem ◽  
Viscous Fluids ◽  
Wall Roughness ◽  
Effective Boundary ◽  
Specific Direction ◽  
Friction Term ◽  
Effective Boundary Conditions

We consider the stationary equations of a general viscous fluid in an infinite (periodic) slab supplemented with Navier's boundary condition with a friction term on the upper part of the boundary. In addition, we assume that the upper part of the boundary is described by a graph of a function φε, where φε oscillates in a specific direction with amplitude proportional to ε. We identify the limit problem when ε → 0, in particular, the effective boundary conditions.

scholarly journals On compressible and piezo-viscous flow in thin porous media

2018 ◽  
Vol 474 (2209) ◽  
pp. 20170601 ◽  
Author(s):  
F. Pérez-Ràfols ◽  
P. Wall ◽  
A. Almqvist
Keyword(s):  
Porous Media ◽  
Pressure Drop ◽  
Viscous Fluid ◽  
Linear Equation ◽  
Nonlinear Function ◽  
Viscous Fluids ◽  
Total Flow ◽  
Thin Porous Media ◽  
Flow Through ◽  
The One

In this paper, we study flow through thin porous media as in, e.g. seals or fractures. It is often useful to know the permeability of such systems. In the context of incompressible and iso-viscous fluids, the permeability is the constant of proportionality relating the total flow through the media to the pressure drop. In this work, we show that it is also relevant to define a constant permeability when compressible and/or piezo-viscous fluids are considered. More precisely, we show that the corresponding nonlinear equation describing the flow of any compressible and piezo-viscous fluid can be transformed into a single linear equation. Indeed, this linear equation is the same as the one describing the flow of an incompressible and iso-viscous fluid. By this transformation, the total flow can be expressed as the product of the permeability and a nonlinear function of pressure, which represents a generalized pressure drop.

Experimental Study of Ship Response due to Internal Viscous Cargo Motions

2018 ◽  
Author(s):  
Virginie Baudry ◽  
Jean-Marc Rousset
Keyword(s):  
Experimental Study ◽  
Free Surface ◽  
Viscous Fluid ◽  
Fresh Water ◽  
Iron Ore ◽  
Experimental Approach ◽  
Viscous Fluids ◽  
Maritime Industry ◽  
Bulk Carrier ◽  
Ship Model

Potential liquefaction of some cargoes (Nickel ore, iron ore, ...) is a major risk for the maritime industry. The difficulties to simulate accurately the behaviour of these materials as well as their interaction with a bulk carrier model leaded us to use a non-Newtonian highly viscous fluid to model a liquefied ore. An experimental approach is presented in this paper. Roll responses of a ship model as well as details on the internal free surface behaviours are investigated for different loading conditions: solid cargo, fresh water and viscous fluids.

scholarly journals A neutrally stable shell in a Stokes flow: a rotational Taylor's sheet

2019 ◽  
Vol 475 (2227) ◽  
pp. 20190178 ◽  
Author(s):  
G. Corsi ◽  
A. De Simone ◽  
C. Maurini ◽  
S. Vidoli
Keyword(s):  
Viscous Fluid ◽  
Phase Speed ◽  
Travelling Wave ◽  
Viscous Fluids ◽  
Swimming Velocity ◽  
Active Materials ◽  
Seminal Paper ◽  
Transversal Displacement ◽  
Stable Equilibria ◽  
Micro Organisms

In a seminal paper published in 1951, Taylor studied the interactions between a viscous fluid and an immersed flat sheet which is subjected to a travelling wave of transversal displacement. The net reaction of the fluid over the sheet turned out to be a force in the direction of the wave phase-speed. This effect is a key mechanism for the swimming of micro-organisms in viscous fluids. Here, we study the interaction between a viscous fluid and a special class of nonlinear morphing shells. We consider pre-stressed shells showing a one-dimensional set of neutrally stable equilibria with almost cylindrical configurations. Their shape can be effectively controlled through embedded active materials, generating a large-amplitude shape-wave associated with precession of the axis of maximal curvature. We show that this shape-wave constitutes the rotational analogue of a Taylor's sheet, where the translational swimming velocity is replaced by an angular velocity. Despite the net force acting on the shell vanishes, the resultant torque does not. A similar mechanism can be used to manoeuver in viscous fluids.

Simulation of the Ultrasonic Diffraction in Viscous Fluids

2003 ◽  
Author(s):  
N. Bouaoua ◽  
A. Alia ◽  
H. Djelouah
Keyword(s):  
Finite Difference ◽  
Viscous Fluid ◽  
Impulse Response ◽  
Acoustic Radiation ◽  
Viscous Fluids ◽  
Attenuation Effect ◽  
Ultrasonic Diffraction ◽  
Response Method ◽  
Good Agreement

In this paper, Impulse Response Method (IRM) and Finite Difference (FD) are used to model the acoustic radiation in a viscous fluid where the attenuation is obeying a squared frequency law. Some results are presented to illustrate the attenuation effect on the diffraction. A good agreement between the IRM results and those numerically predicted by FDM is observed.

Shear flow instability in a conducting viscous fluid

1973 ◽  
Vol 57 (3) ◽  
pp. 481-490
Author(s):  
B. Roberts
Keyword(s):  
Magnetic Field ◽  
Shear Flow ◽  
Viscous Fluid ◽  
Flow Instability ◽  
Approximate Solutions ◽  
Viscous Fluids ◽  
Neutral Stability ◽  
Parallel Magnetic Field ◽  
The Stability ◽  
Shear Flow Instability

The effect of a parallel magnetic field upon the stability of the plane interface between two conducting viscous fluids in uniform relative motion is considered. A parameter reduction, which has not previously been noted, is employed to facilitate the solution of the problem. Neutral stability curves for unrestricted ranges of the governing parameters are found, and the approximate solutions of other authors are examined in this light.

Brownian motion of a colloidal particle near a soft interface

2012 ◽  
Author(s):  
Juan Carlos Benavides-Parra ◽  
Mauricio D. Carbajal-Tinoco ◽  
Agustín Conde-Gallardo ◽  
Eloy Ayón-Beato ◽  
Juan José Godina-Nava ◽  
...  
Keyword(s):  
Brownian Motion ◽  
Colloidal Particle ◽  
Soft Interface

Enhanced flagellar swimming through a compliant viscoelastic network in Stokes flow

2016 ◽  
Vol 792 ◽  
pp. 775-797 ◽  
Author(s):  
Jacek K. Wróbel ◽  
Sabrina Lynch ◽  
Aaron Barrett ◽  
Lisa Fauci ◽  
Ricardo Cortez
Keyword(s):  
Fluid Flow ◽  
Viscous Fluid ◽  
Newtonian Fluid ◽  
Stokes Flow ◽  
Heterogeneous Network ◽  
Three Dimensional ◽  
Viscous Fluids ◽  
Elastic Deformations ◽  
Length Scales ◽  
Polymeric Networks

In many physiological settings, microorganisms must swim through viscous fluids with suspended polymeric networks whose length scales are comparable to that of the organism. Here we present a model of a flagellar swimmer moving through a compliant viscoelastic network immersed in a three-dimensional viscous fluid. The swimmer moves with a prescribed gait, exerting forces on the fluid and the heterogeneous network. The viscoelastic structural links of this network are stretched or compressed in response to the fluid flow caused by these forces, and these elastic deformations also generate forces on the viscous fluid. Here we track the swimmer as it leaves a region of Newtonian fluid, enters and moves through a heterogeneous network and finally enters a Newtonian region again. We find that stiffer networks give a boost to the velocity of the swimmer. In addition, we find that the efficiency of swimming is dependent upon the evolution of the compliant network as the swimmer progresses through it.

Dynamics of Forced Imbibition in Interacting Pores

2019 ◽  
Author(s):  
Aniket S. Ambekar ◽  
Shabina Ashraf ◽  
Jyoti Phirani
Keyword(s):  
Viscous Fluid ◽  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Crucial Role ◽  
Applied Pressure ◽  
Microfluidic Devices ◽  
Viscous Fluids ◽  
Ohnesorge Number ◽  
Viscous Forces ◽  
Wetting Fluid

Abstract Imbibition of viscous fluids in capillaries is important in diagnostics, design of microfluidic devices and enhanced oil recovery. The imbibition of a viscous wetting fluid in a capillary follows Lucas-Washburn law. The Lucas-Washburn regime is only observed when the viscous forces are balanced by the capillary forces. This has been previously described for capillary driven flow as a function of the Ohnesorge number (Oh), the length imbibed by the fluid (x) and the radius (r), for a capillary initially filled with fluid of negligible viscosity, i.e., Ohxr∼1. We show using VOF simulations that, in a capillary of length L initially filled with a viscous fluid, the modified Lucas-Washburn law is observed only if the criterion OhLr∼1 is fulfilled. We use VOF simulations to show the deviation of capillary driven flow from the classical Lucas-Washburn behavior for OhLr∼0.1. VOF simulations for forced imbibition in the regime preceding the Lucas-Washburn regime for a single capillary show that with increase in the applied pressure, the advancement of the meniscus is faster. Forced imbibition dynamics in the interacting capillary geometry are also investigated in this study using VOF simulations. We observe that the leading meniscus in the interacting capillaries is significantly dependent on the applied pressures. We also show using VOF simulations that the wettability of the imbibing fluid plays a crucial role in determining the dynamics in an interacting capillary system.

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