The relaxation of a dewetting contact line is investigated theoretically in
the so-called "Landau-Levich" geometry in which a vertical solid plate is
withdrawn from a bath of partially wetting liquid. The study is performed in
the framework of lubrication theory, in which the hydrodynamics is resolved at
all length scales (from molecular to macroscopic). We investigate the
bifurcation diagram for unperturbed contact lines, which turns out to be more
complex than expected from simplified 'quasi-static' theories based upon an
apparent contact angle. Linear stability analysis reveals that below the
critical capillary number of entrainment, Ca_c, the contact line is linearly
stable at all wavenumbers. Away from the critical point the dispersion relation
has an asymptotic behaviour sigma~|q| and compares well to a quasi-static
approach. Approaching Ca_c, however, a different mechanism takes over and the
dispersion evolves from |q| to the more common q^2. These findings imply that
contact lines can not be treated as universal objects governed by some
effective law for the macroscopic contact angle, but viscous effects have to be
treated explicitly.Comment: 21 pages, 9 figure