Orientation Distribution Function Pattern for Rigid Dumbbell Suspensions in Any Simple Shear Flow

2018 ◽  
Vol 28 (1) ◽  
pp. 1800046 ◽  
Author(s):  
Layal M. Jbara ◽  
Alan Jeffrey Giacomin
Keyword(s):  
Distribution Function ◽  
Shear Flow ◽  
Orientation Distribution Function ◽  
Simple Shear ◽  
Orientation Distribution ◽  
Simple Shear Flow

Observations of fibre orientation in simple shear flow of semi-dilute suspensions

1992 ◽  
Vol 238 ◽  
pp. 277-296 ◽  
Author(s):  
Carl A. Stover ◽  
Donald L. Koch ◽  
Claude Cohen
Keyword(s):  
Shear Flow ◽  
Simple Shear ◽  
Fibre Orientation ◽  
Flow Direction ◽  
Orientation Distribution ◽  
Index Of Refraction ◽  
Simple Shear Flow ◽  
Flow Gradient ◽  
Dilute Suspensions ◽  
Rotary Diffusion

The orientations of fibres in a semi-dilute, index-of-refraction-matched suspension in a Newtonian fluid were observed in a cylindrical Couette device. Even at the highest concentration (nL3 = 45), the particles rotated around the vorticity axis, spending most of their time nearly aligned in the flow direction as they would do in a Jeffery orbit. The measured orbit-constant distributions were quite different from the dilute orbit-constant distributions measured by Anczurowski & Mason (1967b) and were described well by an anisotropic, weak rotary diffusion. The measured ϕ-distributions were found to be similar to Jeffery's solution. Here, ϕ is the meridian angle in the flow-gradient plane. The shear viscosities measured by Bibbo (1987) compared well with the values predicted by Shaqfeh & Fredrickson's theory (1990) using moments of the orientation distribution measured here.

The influence of surface roughness on the particle-pair distribution function of dilute suspensions of non-colloidal spheres in simple shear flow

1997 ◽  
Vol 339 ◽  
pp. 1-24 ◽  
Author(s):  
INDRESH RAMPALL ◽  
JEFFREY R. SMART ◽  
DAVID T. LEIGHTON
Keyword(s):  
Surface Roughness ◽  
Distribution Function ◽  
Shear Flow ◽  
Simple Shear ◽  
Pair Distribution Function ◽  
Closed Orbit ◽  
Particle Surface ◽  
Particle Interaction ◽  
Recognition Algorithm ◽  
Simple Shear Flow

The pair distribution function of 3.18 mm diameter particles was measured in the plane of shear of a simple shear flow at concentrations of 5%, 10% and 15% by volume. A new direct flow-visualization procedure and a new pattern recognition algorithm were used in the investigation. The measurements show a depletion of bound pairs of particles in the direction of flow. A simple model which includes the effect of particle surface roughness on the particle interactions and the pair distribution function is presented. An important effect of surface roughness is that the particles in a suspension can experience irreversible interactions in the presence of an externally imposed simple shear flow. The model shows that such irreversibilities eliminate all bound pairs of particles in the plane of shear by displacing particles out of the closed orbit trajectory region. Surface roughness is found to induce significant asymmetry in the fore and aft region of a two-particle interaction. The measurements and predictions are in qualitative agreement with these conclusions.

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