%0 Generic %1 Bauer2011 %A Bauer, Andreas %A Springel, Volker %D 2011 %K arepo shocks sph turbulence %T Shocking results without shocks: Subsonic turbulence in smoothed particle hydrodynamics and moving-mesh simulations %U http://arxiv.org/abs/1109.4413 %X Highly supersonic, compressible turbulence is thought to be of tantamount importance for star formation processes in the interstellar medium (ISM). Likewise, cosmic structure formation is expected to give rise to subsonic turbulence in the intergalactic medium (IGM), which may substantially modify the thermodynamic structure of gas in virialized dark matter halos and affect small-scale mixing processes in the gas. Numerical simulations have played a key role in characterizing the properties of astrophysical turbulence, but thus far systematic code comparisons have been restricted to the supersonic regime, leaving it unclear whether subsonic turbulence is faithfully represented by the numerical techniques commonly employed in astrophysics. Here we focus on comparing the accuracy of smoothed particle hydrodynamics (SPH) and our new moving-mesh technique AREPO in simulations of driven subsonic turbulence. To make contact with previous results, we also analyze simulations of transsonic and highly supersonic turbulence. We find that the widely employed standard formulation of SPH quite badly fails in the subsonic regime. Instead of building up a Kolmogorov-like turbulent cascade, large-scale eddies are quickly damped close to the driving scale and decay into small-scale velocity noise. In contrast, our moving-mesh technique does yield power-law scaling laws for the power spectra of velocity, vorticity and density, consistent with expectations for fully developed isotropic turbulence. This casts doubt about the reliability of SPH for simulations of cosmic structure formation, especially if turbulence in clusters of galaxies is indeed significant. In contrast, SPH's performance is much better for supersonic turbulence, as here the flow is kinetically dominated and characterized by a network of strong shocks, which can be adequately captured with SPH. Abridged

@misc{Bauer2011, abstract = { Highly supersonic, compressible turbulence is thought to be of tantamount importance for star formation processes in the interstellar medium (ISM). Likewise, cosmic structure formation is expected to give rise to subsonic turbulence in the intergalactic medium (IGM), which may substantially modify the thermodynamic structure of gas in virialized dark matter halos and affect small-scale mixing processes in the gas. Numerical simulations have played a key role in characterizing the properties of astrophysical turbulence, but thus far systematic code comparisons have been restricted to the supersonic regime, leaving it unclear whether subsonic turbulence is faithfully represented by the numerical techniques commonly employed in astrophysics. Here we focus on comparing the accuracy of smoothed particle hydrodynamics (SPH) and our new moving-mesh technique AREPO in simulations of driven subsonic turbulence. To make contact with previous results, we also analyze simulations of transsonic and highly supersonic turbulence. We find that the widely employed standard formulation of SPH quite badly fails in the subsonic regime. Instead of building up a Kolmogorov-like turbulent cascade, large-scale eddies are quickly damped close to the driving scale and decay into small-scale velocity noise. In contrast, our moving-mesh technique does yield power-law scaling laws for the power spectra of velocity, vorticity and density, consistent with expectations for fully developed isotropic turbulence. This casts doubt about the reliability of SPH for simulations of cosmic structure formation, especially if turbulence in clusters of galaxies is indeed significant. In contrast, SPH's performance is much better for supersonic turbulence, as here the flow is kinetically dominated and characterized by a network of strong shocks, which can be adequately captured with SPH. [Abridged] }, added-at = {2011-09-22T18:07:26.000+0200}, author = {Bauer, Andreas and Springel, Volker}, biburl = {https://www.bibsonomy.org/bibtex/2be5caff8e3feaa3c35f0d62e8b517ec3/miki}, description = {[1109.4413] Shocking results without shocks: Subsonic turbulence in smoothed particle hydrodynamics and moving-mesh simulations}, interhash = {eaaf18dcfa9b0c4ecb084943d12b2eed}, intrahash = {be5caff8e3feaa3c35f0d62e8b517ec3}, keywords = {arepo shocks sph turbulence}, note = {cite arxiv:1109.4413 Comment: 17 pages, 15 figures}, timestamp = {2011-09-22T18:07:26.000+0200}, title = {Shocking results without shocks: Subsonic turbulence in smoothed particle hydrodynamics and moving-mesh simulations}, url = {http://arxiv.org/abs/1109.4413}, year = 2011 }