Improving the convergence properties of the moving-mesh code AREPO

Rüdiger Pakmor, Volker Springel, Andreas Bauer, Philip Mocz, Diego J. Munoz, Sebastian T. Ohlmann, Kevin Schaal, Chenchong Zhu

Research output: Contribution to journalArticlepeer-review

164 Scopus citations

Abstract

Accurate numerical solutions of the equations of hydrodynamics play an ever more important role in many fields of astrophysics. In this work, we reinvestigate the accuracy of the movingmesh code AREPO and show how its convergence order can be improved for general problems. In particular, we clarify that for certain problems AREPO only reaches first-order convergence for its original formulation. This can be rectified by simple modifications we propose to the time integration scheme and the spatial gradient estimates of the code, both improving the accuracy of the code. We demonstrate that the new implementation is indeed second-order accurate under the L1 norm, and in particular substantially improves conservation of angular momentum. Interestingly, whereas these improvements can significantly change the results of smooth test problemswe also find that cosmological simulations of galaxy formation are unaffected, demonstrating that the numerical errors eliminated by the new formulation do not impact these simulations. In contrast, simulations of binary stars followed over a large number of orbital times are strongly affected, as here it is particularly crucial to avoid a long-term build up of errors in angular momentum conservation.

Original languageEnglish
Pages (from-to)1134-1143
Number of pages10
JournalMonthly Notices of the Royal Astronomical Society
Volume455
Issue number1
DOIs
StatePublished - 1 Jan 2016
Externally publishedYes

Keywords

  • Formation
  • Galaxy
  • Hydrodynamics
  • Methods
  • Numerical

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