Flow-Driven Compression of a Soft Porous Medium with Friction

Abstract:

Poroelasticity describes situations in which the deformation of a porous medium drives fluid flow, which, in turn, exerts viscous stresses that further deform the medium. Whether in aquifers, glacial till, or biological tissues, flows exhibiting poroelastic coupling are not generally found in isolation; frictional contacts between the solid phase and any confining boundaries strongly influence the nature of the coupling. For the tractable geometry of uniaxial flow through a cylindrical porous medium, we deploy analytic, numerical, and experimental methods to study the effects of wall friction on the properties of large-deformation poroelastic flows in steady state. We first describe an experimental technique for simultaneously measuring the volume flux, solid deformation, and pore pressure gradient in a flow-compressed sponge and present results for a range of pressure heads and sponge aspect ratios. The presence of friction leads to a measurable hysteresis in the volume flux, deformation, and pressure gradient. Using data from a mechanically-compressed sponge to parameterize the frictional input to our theoretical models, we present direct quantitative comparisons between the predictions of our models and the experimentally measured hysteresis of the sponge under flow-driven compression.