Shear-induced resuspension in a couette device

Self-Organized Criticality in Sheared Suspensions

“…The first regime resembles what is obtained in conventional viscous resuspension [14] and corresponds to the highest sedimentation velocities. Sedimentation and shear-induced diffusion compete such that an exponential density profile is established near the bottom, as shown by the dashed line in Fig.…”

“…In the absence of shear, the particles sediment to form a dense random packing at the bottom of the cell. When the system is sheared, particles interact and diffuse upward until the shear-induced diffusion is balanced by the downward sedimentation caused by gravity in a process known as viscous resuspension [14].…”

“…A more realistic sedimentation velocity is given byṽ s ¼ fð c Þv s where fð Þ is a decreasing function of that equals 1 for ¼ 0. Here, we use the hindrance function defined in [14]. Measurements in neutrally buoyant suspensions also show that diffusivity along the z axis scales as D 0 2 ð = c À 1Þ with D 0 % 0:02 AE 0:01d 2 =cycle and % 1:3 AE 0:3.…”

The remarkable longevity of submarine plumes: Implications for the hydrothermal input of iron to the deep-ocean

“…where p is the particle concentration,γ is the local shear strain rate, and k and n are constant coefficients, which vary from one study to another (k = 0.0075 & n = 1 in Da Cunha and Hinch (1996), k = 0.33 & n = 2 in Davis and Leighton (1987); Acrivos et al (1993), k = 0.5 & n = 2 in Leighton and Acrivos (1987a)). Hydrodynamic diffusion can arise under both low-Reynolds number (Leighton and Acrivos, 1987a,b;Schaflinger et al, 1990;Acrivos et al, 1993) and highReynolds number conditions Rampall and Leighton, 1994;Huppert et al, 1995;Ziskind and Gutfinger, 2002).…”

The Rheology of Concentrated Suspensions

“…It arises due to the action of shear-induced particle diffusion (a new mode of particle transport, first identified by the PI and his associates) which induces a flux of particles from the regions of high shear to low and from regions of high particle concentration to low. Our studies have covered flows in channels [1, 6], pipes [3], in supersettlers [5,9] and in a Couette device [2,4,8,11] and we succeeded in showing excellent agreement between theoretical predictions, using model which we had developed earlier, and the experimental results.…”