Guillaume Laibe, Daniel J. Price
In a companion paper (Laibe & Price 2011b), we have presented an algorithm
for simulating two-fluid gas and dust mixtures in Smoothed Particle
Hydrodynamics (SPH). In this paper, we develop an implicit timestepping method
that preserves the exact conservation of the both linear and angular momentum
in the underlying SPH algorithm, but unlike previous schemes, allows the
iterations to converge to arbitrary accuracy and is suited to the treatment of
non- linear drag regimes. The algorithm presented in Paper I is also extended
to deal with realistic astrophysical drag regimes, including both linear and
non-linear Epstein and Stokes drag. The scheme is benchmarked against the test
suite presented in Paper I, including i) the analytic solutions of the dustybox
problem and ii) solutions of the dustywave, dustyshock, dustysedov and
dustydisc obtained with explicit timestepping. We find that the implicit method
is 1- 10 times faster than the explicit temporal integration when the ratio r
between the the timestep and the drag stopping time is 1 < r < 1000.
View original:
http://arxiv.org/abs/1111.3089
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