Anomalous noise distribution of the interface in two-phase fluid flow

The fluctuations of the advancing interface observed in experiments on two-phase fluid flow in porous media are investigated using several evaluation techniques. We find that the amplitudes {η} of these fluctuations are distributed according to a power law of the form P({η}){~}η^-(μ+1), with {μ}{}2.7. Our results together with a recent model of anomalous roughening suggest a plausible explanation for the nonuniversal values of the exponents observed in the experiment on two-phase flow.