Article révisé par les pairs
| Résumé : | Dynamics related to the interplay of viscous fingering with precipitation-driven patterns are studied experimentally in a horizontal Hele-Shaw cell with radial injection. The precipitation reaction, known to produce chemical gardens, involves a cobalt chloride metallic salt solution and a more viscous sodium silicate one. The properties of the fingering precipitation patterns are studied as a function of the flow rate of injection, of the viscosity ratio between the two solutions and of the concentration of the reactants. We show that, for the viscous silicate solution used here, viscous fingering shapes flower-like patterns at low metallic salt concentrations but is not the driving mechanism in the development of spirals and filaments at larger cobalt chloride concentrations. In some cases, enhanced convective motions induced by viscous fingering also increase the amount of precipitate by increasing the mixing between the two reactants. |
