title: Scaling anomalies in the coarsening dynamics of fractal viscous fingering patterns.
abstract: We analyze a recent experiment of Sharon et al. (2003) on the coarsening, due to surface tension, of fractal viscous fingering patterns (FVFPs) grown in a radial Hele-Shaw cell. We argue that an unforced Hele-Shaw model, a natural model for that experiment, belongs to the same universality class as model B of phase ordering. Two series of numerical simulations with model B are performed, with the FVFPs grown in the experiment and with diffusion limited aggregates as the initial conditions. We observed Lifshitz-Slyozov scaling t(1/3) at intermediate distances and slow convergence to this scaling at small distances. Dynamic scale invariance breaks down at large distances.
authors.affiliation: Dipartimento di Matematica e Fisica, Universitá di Camerino, and Istituto Nazionale di Fisica della Materia, 62032 Camerino, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Conti
authors.forename: Azi
authors.initials: A
authors.lastname: Lipshtat
authors.forename: Baruch
authors.initials: B
authors.lastname: Meerson