Porosity effect on the linear stability of flow overlying a porous medium
Perm State University, 15 Bukirev Street, 614990, Perm, Russia
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Accepted: 12 May 2020
Published online: 10 June 2020
We study how the stability of a homogeneous incompressible fluid flow over a saturated Brinkman porous medium is affected by a change in porosity. We produce neutral curves using the shooting method in the area of bimodality. When the porosity decreases, the topology of these curves changes because of the interplay between two instability modes. The long-wave instability is dominant if the medium is highly porous. In contrast, the short-wave instability is the most significant at low porosity because of high tangential stress at the fluid-medium interface. We identify a stability gap between the neutral curve branches within a narrow range of porosity values. The calculated results show the development and disappearance of this gap when the porosity changes.
Key words: Flowing Matter: Liquids and Complex Fluids
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature, 2020