  The origin of chemically peculiar stars and non-zero eccentricity in evolved
close binaries have been long-standing problems in binary stellar evolution.
Answers to these questions may trace back to an intense mass transfer during
AGB binary phase. In this work, we use AstroBEAR to solve the 3D
radiation-hydrodynamic equations and calculate the mass transfer rate in
asymptotic-giant-branch (AGB) binaries that undergo the
wind-Roche-lobe-overflow or Bondi-Hoyle-Lyttleton (BHL) accretion. MESA
produces the density and temperature of the boundary condition of the AGB star.
To improve the resolution of the dynamics of a circumbinary disk, we implement
an azimuthal angle-dependent 3D radiation transfer. We consider optically thin
cooling and obtain the number density of the coolants by solving Saha
equations. One of the goals of this work is to illustrate the transition from
the wind-Roche-lobe-overflow to BHL accretion. Both circumbinary disks and
spiral structure outflows can appear in the simulations. Circumbinary disks may
form when the optical thickness in the equatorial region increases. The
increase of the optical thickness is due to the deflected wind. The resulting
mass transfer efficiency in our models is up to a factor of 8 times higher than
what the standard BHL accretion scenario predicts, and the outflow gains up to
91% of its initial angular momentum when it reaches 1.3 binary separations.
Consequently, some AGB binaries may undergo orbit shrinkage, and some will
expand. The high mass transfer efficiency is closely related to the presence of
the circumbinary disks.
