Abstract
We derive an analytical connection between kinetic relaxation rate and bulk viscosity of a relativistic fluid in d spatial dimensions, all the way from the ultra-relativistic down to the near non-relativistic regime. Our derivation is based on both Chapman-Enskog asymptotic expansion and Grad's method of moments. We validate our theoretical results against a benchmark flow, providing further evidence of the correctness of the Chapman-Enskog approach; we define the range of validity of this approach and provide evidence of mounting departures at increasing Knudsen number. Finally, we present numerical simulations of transport processes in quark-gluon plasmas, with special focus on the effects of bulk viscosity which might prove amenable to future experimental verification. This article is part of the theme issue 'Fluid dynamics, soft matter and complex systems: recent results and new methods'.
| Original language | English |
|---|---|
| Article number | 20190409 |
| Number of pages | 12 |
| Journal | Philosophical Transactions of the Royal Society of London, Series A: Mathematical, Physical and Engineering Sciences |
| Volume | 378 |
| Issue number | 2175 |
| DOIs | |
| Publication status | Published - 10 Jul 2020 |
| Externally published | Yes |
Bibliographical note
Funding Information:Competing interests. We declare we have no competing interest. Funding. The authors thank Victor Ambrus¸ for useful discussions. D.S. has been supported by the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 765048. S.S. acknowledges funding from the European Research Council under the European Union’s Horizon 2020 framework programme (grant no. P/2014-2020)/ERC grant agreement no. 739964 (COPMAT). All the numerical work has been performed on the COKA computing cluster at Università di Ferrara.
Keywords
- bulk viscosity
- quark-gluon plasma
- relativistic hydrodynamics