scholarly journals Enstrophy Cascade in a Model of 2D Turbulence: Comparison with 3D Energy Cascade

1990 ◽  
Vol 84 (3) ◽  
pp. 415-419 ◽  
Author(s):  
K. Ohkitani ◽  
M. Yamada
Keyword(s):  
Energy Cascade ◽  
2D Turbulence ◽  
Enstrophy Cascade

Charney isotropy and equipartition in quasi-geostrophic turbulence

2010 ◽  
Vol 656 ◽  
pp. 448-457 ◽  
Author(s):  
ANDREAS VALLGREN ◽  
ERIK LINDBORG
Keyword(s):  
High Resolution ◽  
Kinetic Energy ◽  
Horizontal Velocity ◽  
Energy Cascade ◽  
Two Dimensional ◽  
Inverse Energy Cascade ◽  
Wide Range ◽  
Geostrophic Turbulence ◽  
Decaying Turbulence ◽  
Enstrophy Cascade

High-resolution simulations of forced quasi-geostrophic (QG) turbulence reveal that Charney isotropy develops under a wide range of conditions, and constitutes a preferred state also in β-plane and freely decaying turbulence. There is a clear analogy between two-dimensional and QG turbulence, with a direct enstrophy cascade that is governed by the prediction of Kraichnan (J. Fluid Mech., vol. 47, 1971, p. 525) and an inverse energy cascade following the classic k−5/3 scaling. Furthermore, we find that Charney's prediction of equipartition between the potential and kinetic energy in each of the two horizontal velocity components is approximately fulfilled in the inertial ranges.

scholarly journals Direct Numerical Simulations to Investigate Energy Transfer between Meso- and Synoptic Scales

2018 ◽  
Vol 75 (4) ◽  
pp. 1163-1171 ◽  
Author(s):  
Masih Eghdami ◽  
Shanti Bhushan ◽  
Ana P. Barros
Keyword(s):  
Energy Source ◽  
Energy Transfer ◽  
Kinetic Energy ◽  
Numerical Simulations ◽  
Direct Numerical Simulations ◽  
Energy Spectra ◽  
Energy Sources ◽  
Synoptic Scale ◽  
2D Turbulence ◽  
Enstrophy Cascade

Abstract Understanding the development of the atmospheric energy spectrum across scales is necessary to elucidate atmospheric predictability. In this manuscript, the authors investigate energy transfer between the synoptic scale and the mesoscale using direct numerical simulations (DNSs) of two-dimensional (2D) turbulence transfer under forcing applied at different scales. First, DNS results forced by a single kinetic energy source at large scales show that the energy spectra slopes of the direct enstrophy cascade are steeper than the theoretically predicted −3 slope. Second, the presence of two inertial ranges in 2D turbulence at intermediate scales is investigated by introducing a second energy source in the meso-α-scale range. The energy spectra for the DNS with two kinetic energy sources exhibit flatter slopes that are closer to −3, consistent with the observed kinetic energy spectra of horizontal winds in the atmosphere at synoptic scales. Further, the results are independent of model resolution and scale separation between the two energy sources, with a robust transition region between the lower synoptic and the upper meso-α scales in agreement with classical observations in the upper troposphere. These results suggest the existence of a mesoscale feedback on synoptic-scale predictability that emerges from the concurrence of the direct (downscale) enstrophy transfer in the synoptic scales and the inverse (upscale) kinetic energy transfer from the mesoscale to the synoptic scale in the troposphere.

scholarly journals STRUCTURE FORMATION IN SPECTRALLY CONDENSED TURBULENCE

2012 ◽  
Vol 19 ◽  
pp. 257-261
Author(s):  
HUA XIA ◽  
MICHAEL SHATS
Keyword(s):  
Structure Formation ◽  
Laboratory Experiments ◽  
Energy Cascade ◽  
Experimental Results ◽  
Two Dimensional ◽  
Radial Transport ◽  
Structural Formation ◽  
2D Turbulence ◽  
Inverse Energy Cascade

Two-dimensional (2D) turbulence supports the inverse energy cascade and the spectral condensate generation, which are studied in laboratory experiments. The generation of the spectral condensation via the inverse energy cascade dramatically reduces the radial transport in 2D flows. In this paper we report experimental results related to the formation of spectral condensates. The dynamics of the structural formation is reposted.

Statistical dynamics of two-dimensional flow

1975 ◽  
Vol 67 (1) ◽  
pp. 155-175 ◽  
Author(s):  
Robert H. Kraichnan
Keyword(s):  
Discrete System ◽  
Computer Experiments ◽  
Negative Temperature ◽  
Energy Cascade ◽  
Positive Temperature ◽  
Two Dimensional ◽  
Dimensional Flow ◽  
Two Dimensional Flow ◽  
Enstrophy Cascade ◽  
The Continuum

The equilibrium statistical mechanics of inviscid two-dimensional flow are re-examined both for a continuum truncated at a top wavenumber and for a system of discrete vortices. In both cases, there are negative-temperature equilibria for finite flows. But for spatially infinite flows, there are only positive-temperature equilibria, and both the continuum and discrete system exhibit proper, extensive, thermodynamic limits a t all realizable values of the energy and enstrophy density. The negative-temperature behaviours of the continuum and discrete system are semi-quantitatively the same, except for a supercondensation phenomenon in the discrete case a t the smallest realizable values of negative temperature. The supercondensed states have very large energy and in them all vortex cores of the same sign are clumped within an area small eompared with the mean area per vortex. The approach of the continuum system to absolute equilibrium by enstrophy cascade to high wavenumbers and energy cascade to low wavenumbers is examined. It is argued that the enstrophy cascade is closely analogous to distortion of a passive scalar field by straining of large spatial scale. This implies that high intermittency of spatial derivatives of the vorticity field can develop but that there is no associated change in the previously proposed log-corrected k−1 enstrophy spectrum law. On the other hand, intermittency build-up in the downward energy cascade can result in a change of the exponent in the energy spectrum law to a negative value of smaller magnitude than 5/3. Intermittency effects in the non-equilibrium energy cascade seem a more plausible explanation for vortex clumping observed in recent computer experiments than do the spatially smooth condensation phenomena associated with the negative-temperature absolute equilibria.

scholarly journals Predictability of the inverse energy cascade in 2D turbulence

2001 ◽  
Vol 13 (4) ◽  
pp. 1060-1062 ◽  
Author(s):  
G. Boffetta ◽  
S. Musacchio
Keyword(s):  
Energy Cascade ◽  
2D Turbulence ◽  
Inverse Energy Cascade
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