Variational Pattern Selection

We address pattern selection problems in nonlinear interface dynamics by maximizing the entropy of the most probable (classical) scenario associated with the processes. This variational principle we applied to well-known selection problems in a Hele-Shaw cell: stationary Saffman-Taylor finger in a channel and self-similar finger in a wedge. The obtained results excellently agree with experiments. We also address the universal fjord opening angle. This principle complements a non-variational selection developed earlier. Surface tension is not needed for selection in both approaches, contrary to the common belief.