Abstract.

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.

Graphical abstract

中文翻译：

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孔隙率对覆盖多孔介质的流体线性稳定性的影响。

摘要。

我们研究了在饱和Brinkman多孔介质上均匀不可压缩流体流动的稳定性如何受孔隙度变化的影响。我们在双峰区域使用射击方法生成中性曲线。当孔隙率降低时，由于两个不稳定模式之间的相互作用，这些曲线的拓扑结构发生了变化。如果介质是高度多孔的，则长波不稳定性是主要的。相反，由于流体-介质界面处的切向应力较高，因此在低孔隙度下，短波不稳定性最明显。我们在孔隙率值的狭窄范围内确定中性曲线分支之间的稳定间隙。计算结果表明，当孔隙率发生变化时，该缝隙的形成和消失。

图形概要