Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hydrodynamical drag in cosmological simulations   We present a study of hydrodynamic drag forces in smoothed particle
simulations. In particular, the deceleration of a resolution-limited cold clump
of gas moving through a hot medium is examined. It is found that the drag for
subsonic velocities exceeds that predicted by simple physical approximations.
This is shown to be a result of the hydrodynamical method which encourages the
accretion of particles from the hot medium onto a shell around the cold clump,
effectively increasing the radius of the clump. For sonic and supersonic
velocities, the drag is shown to be dependent on the effective cross section of
the clump. The consequences for cosmological simulations are discussed.

12
The categories of this paper are: nucl-th
35
The categories of this paper are: mtrl-th
19
The categories of this paper are: eess
9
The categories of this paper are: nlin
32
The categories of this paper are: atom-ph
20
The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph
14
The categories of this paper are: math-ph
15
The categories of this paper are: nucl-ex
16
The categories of this paper are: stat
2
The categories of this paper are: math
29
The categories of this paper are: funct-an
3
The categories of this paper are: physics
37
The categories of this paper are: supr-con
21
The categories of this paper are: adap-org
18
The categories of this paper are: econ