We report on a quantitative test of solvability theory in the case of pattern selection for viscous fingering in a rectangular Hele-Shaw cell. We construct an effective two-dimensional theory that properly takes into account the effect of film draining. In the parameter range where the theory is applicable we find excellent agreement between our predictions and the experimental data. This provides the first precise, quantitative assessment of microscopic solvability in a physical system.

• Received 28 January 1987

DOI:https://doi.org/10.1103/PhysRevA.35.4900