par Maes, Renaud David 
;Rousseaux, Germain ;Scheid, Benoît ;Mishra, Manoranjan ;Colinet, Pierre ;De Wit, Anne
Référence Physics of fluids, 22, page (123104)
Publication Publié, 2010
;Rousseaux, Germain ;Scheid, Benoît ;Mishra, Manoranjan ;Colinet, Pierre ;De Wit, Anne Référence Physics of fluids, 22, page (123104)
Publication Publié, 2010
Article révisé par les pairs
| Résumé : | Experimental studies are conducted to analyze dispersion and miscible viscous fingering of initially circular samples of a given solution displaced linearly at constant speed $U$ by another solution in horizontal Hele-Shaw cells (two glass plates separated by a thin gap). In the stable case of a dyed water sample having the same viscosity as that of displacing non-dyed water, we analyze the transition between dispersive and advective transport of the passive scalar displaced linearly. At low displacement speed and after a certain time, the length of the sample increases as a square root of time allowing to compute the value of a dispersion coefficient. At larger injection speed, the displacement remains advective for the duration of the experiment, with a length of the sample increasing linearly in time. A parametric study allows to gain insight into the switch from one regime to the other as a function of the gap width of the cell. In the unstable case of viscous glycerol samples displaced by dyed water, the rear interface of the sample where less viscous water pushes more viscous glycerol is unstable with regard to viscous fingering. The interface deforms into fingers, the number and size of which depend on the viscosity ratio between the two solutions and on the displacement speed. We study the influence of these viscous fingering phenomena on the increased spreading of the sample for various mobility ratios and injection speeds. |
