Suspensions of non-Brownian particles in complex fluids: Rheology, microstructure and fluid mechanics*

Suspensions of non-Brownian particles in complex fluids (hereafter
complex slurries) are relevant in industrial processes (e.g. waste
disposal, concrete, drilling muds, metalworking chip transport, and food
processing) and in natural phenomena (e.g. flows of slurries, debris,
and lava). It is also relevant to mention that some biological and smart
materials can be designed from various suspensions, drawing attention to
applications in physiology, bio-locomotion and shock absorbers. This
countless number of suspensions has a wide range of nonlinear
rheological behaviors, such as shear thinning, shear thickening, shear
banding, yield stress, and finite normal stress differences even when
inertia is negligible.

This talk will introduce an array of experimental and modeling
techniques that my research team uses to investigate rheological
properties and fluid dynamical behavior of the complex slurries. The
goal is to establish a continuum framework and refine it through a
series of microstructure investigations. This continuum framework is
formulated and explained via a mean field study, homogenization theory,
as well as a computational study based on the Immersed Boundary Method.
In addition, it will be presented that how confinement effects
transition a suspension from one rheological behavior to another and how
these observations can be explained beyond the framework of the mean
field approaches. Finally, open questions will be disclosed, which must
be answered in order to build a firm foundation for a long-term
contribution to the area of complex slurries.