Particle Motions in Sheared Suspensions. XXVIII. Configurations of Coiled Fibers in Shear Flow

1975 ◽  
Vol 53 (18) ◽  
pp. 2689-2694 ◽  
Author(s):  
A. Okagawa ◽  
S. G. Mason
Keyword(s):  
Steady State ◽  
Shear Flow ◽  
Velocity Gradient ◽  
Spherical Symmetry ◽  
Orthogonal Axis ◽  
The Third ◽  
End To End ◽  
Sheared Suspensions

The coiling of elastomer filaments in liquids undergoing shear flow was studied experimentally. In the steady state the rotating coils were stretched along the axes of flow and vorticity, compacted along the third orthogonal axis, and became progressively more entangled as the velocity gradient increased. Although the coils did not possess spherical symmetry, the distribution of end-to-end distances and maximum projected dimensions projected on a given axis or plane corresponded closely to random coiling statistics.

On the anisotropic response of a Janus drop in a shearing viscous fluid

2015 ◽  
Vol 770 ◽  
Author(s):  
Misael Díaz-Maldonado ◽  
Ubaldo M. Córdova-Figueroa
Keyword(s):  
Shear Flow ◽  
Velocity Gradient ◽  
External Flow ◽  
Bodies Of Revolution ◽  
Internal Interface ◽  
Equal Radius ◽  
Fluid Drop ◽  
Resistance Matrix ◽  
Shearing Motion ◽  
Unbounded Fluid

The force and couple that result from the shearing motion of a viscous, unbounded fluid on a Janus drop are the subjects of this investigation. A pair of immiscible, viscous fluids comprise the Janus drop and render it with a ‘perfect’ shape: spherical with a flat, internal interface, in which each constituent fluid is bounded by a hemispherical domain of equal radius. The effect of the arrangement of the internal interface (drop orientation) relative to the unidirectional shear flow is explored within the Stokes regime. Projection of the external flow into a reference frame centred on the drop simplifies the analysis to three cases: (i) a shear flow with a velocity gradient parallel to the internal interface, (ii) a hyperbolic flow, and (iii) two shear flows with a velocity gradient normal to the internal interface. Depending on the viscosity of the internal fluids, the Janus drop behaves as a simple fluid drop or as a solid body with broken fore and aft symmetry. The resultant couple arises from both the straining and swirling motions of the external flow in analogy with bodies of revolution. Owing to the anisotropic resistance of the Janus drop, it is inferred that the drop can migrate lateral to the streamlines of the undisturbed shear flow. The grand resistance matrix and Bretherton constant are reported for a Janus drop with similar internal viscosities.

Numerical study of electric field effects on the deformation of two-dimensional liquid drops in simple shear flow at arbitrary Reynolds number

2009 ◽  
Vol 626 ◽  
pp. 367-393 ◽  
Author(s):  
STEFAN MÄHLMANN ◽  
DEMETRIOS T. PAPAGEORGIOU
Keyword(s):  
Steady State ◽  
Shear Flow ◽  
Electric Field ◽  
Electric Fields ◽  
Simple Shear ◽  
Simple Shear Flow ◽  
Physical Parameters ◽  
Shear Stresses ◽  
Two Dimensional ◽  
Liquid Drops

The effect of an electric field on a periodic array of two-dimensional liquid drops suspended in simple shear flow is studied numerically. The shear is produced by moving the parallel walls of the channel containing the fluids at equal speeds but in opposite directions and an electric field is generated by imposing a constant voltage difference across the channel walls. The level set method is adapted to electrohydrodynamics problems that include a background flow in order to compute the effects of permittivity and conductivity differences between the two phases on the dynamics and drop configurations. The electric field introduces additional interfacial stresses at the drop interface and we perform extensive computations to assess the combined effects of electric fields, surface tension and inertia. Our computations for perfect dielectric systems indicate that the electric field increases the drop deformation to generate elongated drops at steady state, and at the same time alters the drop orientation by increasing alignment with the vertical, which is the direction of the underlying electric field. These phenomena are observed for a range of values of Reynolds and capillary numbers. Computations using the leaky dielectric model also indicate that for certain combinations of electric properties the drop can undergo enhanced alignment with the vertical or the horizontal, as compared to perfect dielectric systems. For cases of enhanced elongation and alignment with the vertical, the flow positions the droplets closer to the channel walls where they cause larger wall shear stresses. We also establish that a sufficiently strong electric field can be used to destabilize the flow in the sense that steady-state droplets that can exist in its absence for a set of physical parameters, become increasingly and indefinitely elongated until additional mechanisms can lead to rupture. It is suggested that electric fields can be used to enhance such phenomena.

Elastic recovery of immiscible blends 1. Analysis after steady state shear flow

1999 ◽  
Vol 38 (1) ◽  
pp. 65-72 ◽  
Author(s):  
I. Vinckier ◽  
P. Moldenaers ◽  
J. Mewis
Keyword(s):  
Steady State ◽  
Shear Flow ◽  
Elastic Recovery ◽  
Immiscible Blends

scholarly journals SMOS Third Mission Reprocessing after 10 Years in Orbit

2020 ◽  
Vol 12 (10) ◽  
pp. 1645 ◽  
Author(s):  
Roger Oliva ◽  
Manuel Martín-Neira ◽  
Ignasi Corbella ◽  
Josep Closa ◽  
Albert Zurita ◽  
...  
Keyword(s):  
Image Reconstruction ◽  
Third Mission ◽  
The Third ◽  
The Past ◽  
Level 1 ◽  
End To End ◽  
The One

After more than 10 years in orbit, the SMOS team has started a new reprocessing campaign for the SMOS measurements, which includes the changes in calibration and image reconstruction that have been made to the Level 1 Operational Processor (L1OP) during the past few years. The current L1 processor, version v620, was used for the second mission reprocessing in 2014. The new version, v724, is the one run in the third mission reprocessing and will become the new operational processor. The present paper explains the major changes applied and analyses the quality of the data with different metrics. The results have been obtained with numerous individual tests that have confirmed the benefits of the evolutions and an end-to-end processing campaign involving three years of data used to assess the improvements of the SMOS measurements quantitatively.

A Novel Method to Order Nanowire Based on Macrofludic System

2014 ◽  
Vol 1015 ◽  
pp. 32-36
Author(s):  
Ting Zhong Xu ◽  
Hebibul Rahman ◽  
Li Bo Zhao ◽  
Yu Long Zhao ◽  
Zhuang De Jiang
Keyword(s):  
Molecular Dynamics ◽  
Shear Flow ◽  
Velocity Gradient ◽  
Rotational Speed ◽  
Md Simulation ◽  
Bulk Material ◽  
Economical Method ◽  
Uniform Velocity ◽  
Novel Method

The rheology of nanowires (NWs) and nanotubes (NTs) in shear flow has been analyzed by molecular dynamics (MD) simulation and macrofludic simulation. A method based on macrofludic system for aligning NWs and NTs is demonstrated. In this method, vortex is generated near the surface of a plane by using a mushroom like turnplate. Then a uniform velocity gradient was generated on the surface of the plane. Through controlling the rotational speed of the turnplate, the rheology of NWs and NTs in suspension can be easily controlled. So it provides a more effective and economical method for the alignment of NWs and NTs, as well as forming the anisotropy NWs and NTs bulk material.

The effect of weak Brownian rotations on particles in shear flow

1971 ◽  
Vol 46 (4) ◽  
pp. 685-703 ◽  
Author(s):  
L. G. Leal ◽  
E. J. Hinch
Keyword(s):  
Reynolds Number ◽  
Steady State ◽  
Probability Distribution ◽  
Shear Flow ◽  
Equilibrium Distribution ◽  
Steady State Probability ◽  
Bulk Properties ◽  
Closed Orbits ◽  
Basic Equations

Axisymmetric particles in zero Reynolds number shear flow execute closed orbits. In this paper we consider the role of small Brownian couples in establishing a steady-state probability distribution for a particle being on any particular orbit. After presenting the basic equations, we derive an expression for the equilibrium distribution. This result is then used to calculate some bulk properties for a suspension of such particles, and these predicted properties are compared with available experimental observation.

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