Damping of CO2 convective dissolution by a forced horizontal transverse flow

This study investigates the gravitational instability induced by carbon dioxide (CO2) dissolution in the presence of a forced horizontal flow, using a vertical Hele-Shaw cell filled with water. CO2 forms an unstable diffusive layer at the top of the liquid, which evolves into downward convective motion. A pH-sensitive dye is used to measure quantitatively the fingering patterns. It is observed that a transverse flow has a stabilizing effect on the gravitational instability: at low translation velocities, the effect is negligible, but beyond a threshold, the onset of the instability is delayed, with slower growth and increased wavelength. This behavior is explained by Taylor-Aris dispersion, and a theoretical model is proposed to account for the observed scaling laws. Finally, the CO2 flux in the nonlinear regime is slightly reduced by the transverse flow.