Daisuke Kawata, Takashi Okamoto, Brad K. Gibson, David J. Barnes, Renyue Cen
We adapt a modern scheme of smoothed particle hydrodynamics (SPH) to our tree N-body/SPH galactic chemodynamics code GCD+. The applied scheme includes imple- mentations of the artificial viscosity switch and artificial thermal conductivity pro- posed by Morris (1997), Rosswog & Price (2007) and Price (2008), to model disconti- nuities and Kelvin-Helmholtz instabilities more accurately. We first present hydrody- namics test simulations and contrast the results to runs undertaken without artificial viscosity switch or thermal conduction. In addition, we also explore the different levels of smoothing by adopting larger or smaller smoothing lengths, i.e. a larger or smaller number of neighbour particles, Nnb. We demonstrate that the new version of GCD+ is capable of modelling Kelvin-Helmholtz instabilities to a similar level as the mesh code, Athena. From the Gresho vortex and point-like explosion tests, we conclude that setting the smoothing length to keep the number of neighbour particles as high as Nnb~58 is preferable to adopting smaller smoothing lengths. We present our optimised parameter sets from the hydrodynamics tests.
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http://arxiv.org/abs/0902.4002
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