Spatial fluctuations in flow through a deformable porous medium

Fluid flow through a deformable porous medium, such as a filter cake or a biological tissue, is typically modeled by combining Darcy’s law with a solid stress balance. Unfortunately, this continuum picture neglects flow fluctuations inside the pore space. These fluctuations can impact solute dispersal in such processes as filter-cake washing and nutrient transport in tissues. Additionally, this method neglects variations in the stress within the solid matrix, which can further alter the variability in the fluid flow. We use direct visualization to disentangle this coupling between solid stresses and fluid flow in model deformable porous media. Specifically, we use confocal microscopy to characterize how the spatial fluctuations in the flow are altered by deformations of the solid matrix. Our results thus shed light on the pore-scale complexity that is hidden in continuum models.