Gravitational instability due to the dissolution of carbon dioxide in a Hele-Shaw cell - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Physical Review Fluids Année : 2016

Gravitational instability due to the dissolution of carbon dioxide in a Hele-Shaw cell

Résumé

We present an experimental study of the gravitational instability triggered by dissolution of carbon dioxide through a water-gas interface. We restrict the study to vertical parallelepipedic Hele-Shaw geometries, for which the thickness is smaller than the other dimensions. The partial pressure of carbon dioxide is quickly increased, leading to a denser layer of CO2-enriched water underneath the surface. This initially one-dimensional diffusive layer destabilizes through a convection-diffusion process. The concentration field of carbon dioxide, which is visualized by means of a pH-sensitive dye, shows a fingering pattern whose characteristics (wavelength and amplitude growth rate) are functions of the Rayleigh (Ra) and the Darcy (Da) numbers. At low Rayleigh numbers, the growth rate and the wave numbers are independent of the Rayleigh number and in excellent agreement with the classical results obtained numerically and theoretically in the Darcy regime. However, above a threshold of Ra√Da of the order of 10, the growth rate and the wave number strongly decrease due to the Brinkman term associated with the viscous diffusion in the vertical and longitudinal directions. In this Darcy-Brinkman regime, the growth rate and the wave number depend only on the thickness-based Rayleigh number Ra√Da. The classical Rayleigh-Taylor theory including the Brinkman term has been extended to this diffusive gravitational instability and gives an excellent prediction of the growth rate over four decades of Rayleigh numbers. However, the Brinkman regime seems to be valid only until Ra√Da = 1000. Above this threshold, the transverse velocity profile is no longer parabolic, which leads to an overestimation of the wave number by the theory.
Fichier non déposé

Dates et versions

hal-01390584 , version 1 (02-11-2016)

Identifiants

  • HAL Id : hal-01390584 , version 1

Citer

Alexander Vreme, François Nadal, Bernard Pouligny, Gérard Liger-Belair, P. Jeandet, et al.. Gravitational instability due to the dissolution of carbon dioxide in a Hele-Shaw cell. Physical Review Fluids, 2016. ⟨hal-01390584⟩
126 Consultations
0 Téléchargements

Partager

Gmail Facebook X LinkedIn More