[論文レビュー] Scale Collapse of Vortices at Porous-Fluid Interfaces

Justin Courter, Vishal Srikanth+2 more|arXiv (Cornell University)|Jan 15, 2026

Heat and Mass Transfer in Porous Media被引用数 0

ひとこと要約

paper shows that macroscale vortices abruptly collapse at porous-fluid interfaces across high porosities and that pore-scale geometry governs turbulence within the porous medium, regardless of external forcing.

ABSTRACT

The interaction between externally generated turbulence and porous media is central to many engineering and environmental flows, yet the fate of macroscale vortical structures at a porous/fluid interface remains uncharacterized. By numerically simulating the turbulent flow, we investigate the penetration, breakdown, and turbulence kinetic energy (TKE) transport of macroscale vortices impinging on porous matrices with high porosities $ϕ$ = 0.80-0.95. For all porosities considered, macroscale vortices collapse abruptly at the porous interface and do not persist within the matrix, supporting the pore-scale prevalence of turbulence even under strong external forcing. Although vortex impingement injects TKE into the porous medium through turbulent transport at the interface, this supplied TKE is rapidly redistributed and dissipated as the flow reorganizes to satisfy pore-scale geometric constraints. Deeper within the porous layer, turbulence is sustained primarily by local shear production associated with pore-scale velocity gradients, and the internal flow becomes increasingly independent of upstream conditions. Variations in porosity modulate the relative balance between production and dissipation by altering geometric confinement and effective Reynolds number, but the dominant turbulent length scale within the porous matrix remains set by the pore size. These results demonstrate that porous media act as a robust geometric filter that enforces pore-scale-dominated turbulence regardless of the external forcing.

研究の動機と目的

• Investigate the fate of macroscale vortical structures impinging on porous media with high porosity (φ = 0.80–0.95).
• Characterize penetration, breakdown, and turbulence kinetic energy transport across the porous–fluid interface.
• Determine how porosity influences production, dissipation, and turbulence distribution inside the porous layer.

提案手法

• Numerically simulate turbulent flow interacting with porous matrices at high porosities (φ = 0.80–0.95).
• Track the collapse and absence of macroscale vortices within the porous matrix.
• Analyze turbulence transport at the interface and redistribution/dissipation of TKE inside the porous medium.
• Assess how pore-scale velocity gradients drive internal shear production and sustain turbulence.
• Examine how porosity modulates the balance between production and dissipation via confinement and effective Reynolds number.

実験結果

リサーチクエスチョン

• RQ1 Do macroscale vortices persist inside porous matrices with high porosity when externally forced by turbulence?
• RQ2 How is turbulence kinetic energy transported and redistributed at the porous-fluid interface and within the porous medium?
• RQ3 What role do pore-scale geometry and porosity play in determining the dominant turbulent mechanisms inside the porous layer?

主な発見

• Macroscale vortices collapse abruptly at the porous interface and do not persist within the matrix for all porosities studied.
• Vortex impingement injects TKE into the porous medium via interfacial turbulent transport, but this TKE is rapidly redistributed and dissipated as the flow reconfigures to pore-scale constraints.
• Inside the porous layer, turbulence is mainly sustained by local shear production from pore-scale velocity gradients and becomes increasingly independent of upstream conditions.
• The dominant turbulent length scale within the porous matrix remains set by the pore size.
• Porosity variations modulate the balance between production and dissipation by altering geometric confinement and effective Reynolds number, but the internal turbulence remains pore-scale dominated