EXPERIMENTAL PERTURBATIONS TO SAFFMAN-TAYLOR FLOW

Patterns found at driven interfaces add richness and beauty to the visual world, but they build processing-history-dependent inhomogeneities into samples of materials whose usefulness is affected by these inhomogeneities. The Saffman-Taylor (S-T) problem provides a particularly simple case of nonlinear interfacial pattern formation. A wide variety of experiments have added perturbations to the S-T problem in order to learn more about the dynamics of driven interfaces and about the relation of material properties to dynamical pattern evolution.