  We study the effects of the tidal interaction with the companion, via orbital
separation and binary mass ratio, on the global one-armed oscillation modes in
disks around binary Be stars. Our model takes into account the
three-dimensional effect that contributes to the mode confinement, which was
recently found by Ogilvie(2008). We find that the one-armed oscillations are
well confined in systems with disks larger than a few tens of stellar radii. In
such systems, the oscillation period depends little on the binary parameters.
On the other hand, in systems with smaller disks, where the mode confinement is
incomplete, the oscillation period increases with increasing orbital separation
and/or decreasing binary mass ratio. The eigenmode is insensitive to the
spectral type of the central star. Our results suggest that the dependence of
V/R oscillation period on the orbital separation and binary mass ratio should
be observed only in short period binary systems, and that, for systems with a
similar orbital period, those with higher mass ratios will show shorter V/R
variations.
