Author(s): Areej Sabr Mohammed, Alaa Kadhim Mohammed

Abstract: Fluid flow in porous channels is ubiquitous in engineering and environmental processes, such as filtration devices, geothermal energy, oil reservoirs, catalytic reactors, thermal management equipment, and porous heat exchangers. The permeability of the porous medium has a strong influence on the stability of such flows. Although many previous studies have focused on homogeneous porous media, real porous materials often have spatially variable permeability due to manufacturing defects, heterogeneity in pore distributions, degradation of materials or natural variations in geology. In the present work, the hydrodynamics and instability features of an incompressible flow through a porous channel with non-uniform permeability are studied numerically. The Darcy–Brinkman model is used to represent viscous diffusion and resistance due to the porous medium. The permeability is modeled as a spatially varying field, so that the influence of permeability gradients and intensity of heterogeneity can be systematically investigated. The governing equations are nondimensionalized using the Reynolds number and the Darcy number, and the heterogeneity of the permeability is measured by a permeability-variation parameter. A two-dimensional model is developed to study the velocity profile, pressure loss, streamline pattern, wall shear and onset of flow instability. It is shown that the variation of the permeability in space distorts the velocity profile of the base flow and leads to spatially localized regions of flow acceleration and deceleration. Increasing permeability heterogeneity leads to larger velocity gradients and rearrangement of pressure, thereby significantly affecting the stability characteristics as compared with that of the homogeneous porous channel. The results highlight that the permeability distribution, rather than only its spatially averaged value, is the key quantity for predicting the flow stability of porous-channel systems. The presented numerical framework can serve as a useful guide for designing porous-flow systems with tailored transport and stability features.

DOI: https://www.doi.org/10.22271/27078043.2026.v7.i2b.143

Pages: 110-119 | Views: 36 | Downloads: 12

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