Tyler Lutz

Fluid flow through deformable, porous materials is seemingly ubiquitous in the natural world—spanning length scales from the cellular to the planetary—and offers a phenomenologically rich setting in which to study the generally nonlinear coupling between solid- and fluid-mechanics in multiphase materials. As much as we might like to study such flows in strict isolation from their environment, this thesis argues that properly accounting for forces that arise on the boundaries of such flows is essential to understanding the behavior of realistic soft porous media flows. Building on an experimental program initiated more than half a century ago, we demonstrate a novel empirical method for simultaneously measuring the pore pressure and medium deformation profiles alongside the volume flux in uniaxial porous media flow. We perform a suite of experiments studying the flow-compaction of a foam sample in a regime in which the friction between the sample and boundaries of the experimental cell cannot be ignored. By opposing the motion of the foam, the wall friction leads to a demonstrable hysteresis in all of the measured quantities, a path-dependence which is difficult to account for in conventional theoretical models of large-deformation poroelasticity. Our experimental measurements constrain the material constitutive relations of our foam sample and thus enable us to formulate a mathematically closed theory of its poroelastic dynamics. Informed by these closures, we develop a particle-based theoretical framework that accounts for both static and kinetic frictional effects, and we demonstrate that our model quantitatively captures the full friction-induced phenomenology evinced in our experiments.