title: Variations of characteristic time scales in rotating stratified turbulence using a large parametric numerical study.
abstract: We study rotating stratified turbulence (RST) making use of numerical data stemming from a large parametric study varying the Reynolds, Froude and Rossby numbers, Re, Fr and Ro in a broad range of values. The computations are performed using periodic boundary conditions on grids of 1024(3) points, with no modeling of the small scales, no forcing and with large-scale random initial conditions for the velocity field only, and there are altogether 65 runs analyzed in this paper. The buoyancy Reynolds number defined as R(B) = ReFr2 varies from negligible values to ≈ 10(5), approaching atmospheric or oceanic regimes. This preliminary analysis deals with the variation of characteristic time scales of RST with dimensionless parameters, focusing on the role played by the partition of energy between the kinetic and potential modes, as a key ingredient for modeling the dynamics of such flows. We find that neither rotation nor the ratio of the Brunt-Väisälä frequency to the inertial frequency seem to play a major role in the absence of forcing in the global dynamics of the small-scale kinetic and potential modes. Specifically, in these computations, mostly in regimes of wave turbulence, characteristic times based on the ratio of energy to dissipation of the velocity and temperature fluctuations, T(V) and T(P), vary substantially with parameters. Their ratio γ=T(V)/T(P) follows roughly a bell-shaped curve in terms of Richardson number Ri. It reaches a plateau - on which time scales become comparable, γ≈0.6 - when the turbulence has significantly strengthened, leading to numerous destabilization events together with a tendency towards an isotropization of the flow.
authors.affiliation: Oak Ridge National Laboratory, National Center for Computational Sciences, P.O. Box 2008, 37831, Oak Ridge, TN, USA.|SciTec, Inc., 100 Wall St., 08540, Princeton, NJ, USA.
authors.forename: D
authors.initials: D
authors.lastname: Rosenberg
authors.affiliation: École Normale Supérieure, F-69007, Lyon, France.|Space Sciences Laboratory, University of California, 94720, Berkeley, CA, USA.
authors.forename: R
authors.initials: R
authors.lastname: Marino
authors.affiliation: Department of Physics of Complex Systems, Weizmann Institute of Science, 76100, Rehovot, Israel.
authors.forename: C
authors.initials: C
authors.lastname: Herbert
authors.affiliation: Laboratory for Atmospheric and Space Physics, University of Colorado, 80309, Boulder, CO, USA. pouquet@ucar.edu.|National Center for Atmospheric Research, P.O. Box 3000, 80307, Boulder, CO, USA. pouquet@ucar.edu.
authors.forename: A
authors.initials: A
authors.lastname: Pouquet
keywords: Topical Issue: Multi-scale phenomena in complex flows and flowing matter
references.citation: Phys Rev E Stat Nonlin Soft Matter Phys. 2014 Aug;90(2):023005
references.pmid: 25215818
references.citation: Phys Rev Lett. 2009 Jul 3;103(1):014501
references.pmid: 19659150
references.citation: Phys Rev Lett. 2007 Apr 13;98(15):154501
references.pmid: 17501356
references.citation: Phys Rev E Stat Nonlin Soft Matter Phys. 2002 Aug;66(2 Pt 2):026301
references.pmid: 12241279
references.citation: Proc Natl Acad Sci U S A. 2014 Mar 25;111 Suppl 1:4727-34
references.pmid: 24704881
references.citation: Phys Rev E Stat Nonlin Soft Matter Phys. 2014 Aug;90(2):023018
references.pmid: 25215831
references.citation: Phys Rev E Stat Nonlin Soft Matter Phys. 2013 Jun;87(6):063007
references.pmid: 23848772
references.citation: Phys Rev E Stat Nonlin Soft Matter Phys. 2009 Aug;80(2 Pt 2):025401
references.pmid: 19792189
references.citation: Phys Rev Lett. 2015 Mar 20;114(11):114504
references.pmid: 25839278
references.citation: Science. 2011 Apr 15;332(6027):318-22
references.pmid: 21393512
references.citation: Phys Rev Lett. 1995 Oct 23;75(17):3114-3117
references.pmid: 10059498
references.citation: Phys Rev E Stat Nonlin Soft Matter Phys. 2014 Apr;89(4):043002
references.pmid: 24827327
references.citation: Phys Rev E Stat Nonlin Soft Matter Phys. 2003 Sep;68(3 Pt 2):036308
references.pmid: 14524891
references.citation: Phys Rev Lett. 2007 Oct 19;99(16):164501
references.pmid: 17995256
references.citation: Phys Rev E Stat Nonlin Soft Matter Phys. 2003 Jul;68(1 Pt 2):015301
references.pmid: 12935189
references.citation: Phys Rev E Stat Nonlin Soft Matter Phys. 2004 Jun;69(6 Pt 2):066608
references.pmid: 15244765
references.citation: Phys Rev Lett. 2009 Jul 24;103(4):044501
references.pmid: 19659360