Flow and topological structures of viscoelastic fluids across a partially blocked porous medium in a confined channel

This study numerically investigates the flow characteristics and topological structures of the Giesekus viscoelastic fluid across a partially blocked porous medium in the laminar flow regime. The porous mediums consist of a series of uniformly or hexagonal arranged square columns. The pore-scale hydrodynamic interactions influenced by the rheological properties and geometric structure of porous media are explored. The results show that momentum transfer occurs at the permeable interface between the porous and non-porous regions. The stress distribution indicates that as elasticity decreases and shear-thinning effect intensifies, the overall flow stress is reduced. By adjusting the size of a single square obstacle, the stretching of polymer chains and flow topology illustrate that as the solid fraction increases, shear flow gradually becomes dominant. Furthermore, comparing the flow of porous media with square and hexagonal arrangements, the tortuosity of the hexagonal path inhibits the disappearance of stretching and rotational flows. These findings illustrate the microscopic flow mechanism of viscoelastic fluids in intricate porous structures, providing a scientific foundation for optimizing the design and control of industrial processes that involve complex fluids passing through such porous materials.