Passive scalar dispersion along porous stratum with natural convection
Fuente:
arXiv
Gespeichert in:
| Hauptverfasser: | , , |
|---|---|
| Format: | Preprint |
| Veröffentlicht: |
2025
|
| Schlagworte: | |
| Online-Zugang: | |
| Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
| _version_ | 1866916674184151040 |
|---|---|
| author | Hu, Chenglong Xu, Ke Yang, Yantao |
| author_facet | Hu, Chenglong Xu, Ke Yang, Yantao |
| contents | We investigate horizontal dispersion of a passive scalar in a porous stratum with Rayleigh-Darcy convection initiated by a geothermal gradient. While increasing Rayleigh number ($Ra$) keeps enhancing convection, the horizontal dispersion coefficient ($\hat{D}$) only scales with Ra in a narrow range, and saturates at $Ra \gtrsim 2500$. We rationalize this two-stage behavior: at low Ra, passive scalar migrates through bulk circumflex; at high Ra, boundary micro-plume layer becomes the dominant scalar pathway. Theory gives saturate $\hat{D}$ value proportional to the Lewis number $Le$ and molecular diffusivity $D_0$. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2504_03545 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Passive scalar dispersion along porous stratum with natural convection Hu, Chenglong Xu, Ke Yang, Yantao Fluid Dynamics We investigate horizontal dispersion of a passive scalar in a porous stratum with Rayleigh-Darcy convection initiated by a geothermal gradient. While increasing Rayleigh number ($Ra$) keeps enhancing convection, the horizontal dispersion coefficient ($\hat{D}$) only scales with Ra in a narrow range, and saturates at $Ra \gtrsim 2500$. We rationalize this two-stage behavior: at low Ra, passive scalar migrates through bulk circumflex; at high Ra, boundary micro-plume layer becomes the dominant scalar pathway. Theory gives saturate $\hat{D}$ value proportional to the Lewis number $Le$ and molecular diffusivity $D_0$. |
| title | Passive scalar dispersion along porous stratum with natural convection |
| topic | Fluid Dynamics |
| url | https://arxiv.org/abs/2504.03545 |