On calculating the potential vorticity flux
Abstract
We discuss and compare different approaches to calculating the dynamics of anisotropic flow structure formation in quasi twodimensional turbulence based on potential vorticity (PV) transport in real space. The general structure of the PV flux in the relaxation processes is deduced nonperturbatively. The transport coefficients of the PV flux are then systematically calculated using perturbation theory. We develop two nonperturbative relaxation models: the first is a mean field theory for the dynamics of minimum enstrophy relaxation based on the requirement that the mean flux of PV dissipates total potential enstrophy but conserves total fluid kinetic energy. The results show that the structure of PV flux has the form of a sum of a positive definite hyperviscous and a negative or positive viscous flux of PV. Turbulence spreading is shown to be related to PV mixing via the link of turbulence energy flux to PV flux. In the relaxed state, the ratio of the PV gradient to zonal flow velocity is homogenized. This homogenized quantity sets a constraint on the amplitudes of PV and zonal flow in the relaxed state. The second relaxation model is derived from symmetry principles alone. The form of PV flux contains a nonlinear convective term inmore »
 Authors:
 Center for Astrophysics and Space Sciences and Department of Physics, University of California San Diego, La Jolla, California 920930424 (United States)
 Publication Date:
 OSTI Identifier:
 22423777
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Physics of Plasmas; Journal Volume: 22; Journal Issue: 3; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; AMPLITUDES; FLOW RATE; FLUID FLOW; KINETIC ENERGY; LIMITING VALUES; MEANFIELD THEORY; PARAMETRIC INSTABILITIES; PERTURBATION THEORY; RELAXATION; SHEAR; SPECTRA; SYMMETRY; TURBULENCE; TWODIMENSIONAL CALCULATIONS; VISCOSITY; VORTICES
Citation Formats
Hsu, PeiChun, and Diamond, P. H. On calculating the potential vorticity flux. United States: N. p., 2015.
Web. doi:10.1063/1.4916401.
Hsu, PeiChun, & Diamond, P. H. On calculating the potential vorticity flux. United States. doi:10.1063/1.4916401.
Hsu, PeiChun, and Diamond, P. H. 2015.
"On calculating the potential vorticity flux". United States.
doi:10.1063/1.4916401.
@article{osti_22423777,
title = {On calculating the potential vorticity flux},
author = {Hsu, PeiChun and Diamond, P. H.},
abstractNote = {We discuss and compare different approaches to calculating the dynamics of anisotropic flow structure formation in quasi twodimensional turbulence based on potential vorticity (PV) transport in real space. The general structure of the PV flux in the relaxation processes is deduced nonperturbatively. The transport coefficients of the PV flux are then systematically calculated using perturbation theory. We develop two nonperturbative relaxation models: the first is a mean field theory for the dynamics of minimum enstrophy relaxation based on the requirement that the mean flux of PV dissipates total potential enstrophy but conserves total fluid kinetic energy. The results show that the structure of PV flux has the form of a sum of a positive definite hyperviscous and a negative or positive viscous flux of PV. Turbulence spreading is shown to be related to PV mixing via the link of turbulence energy flux to PV flux. In the relaxed state, the ratio of the PV gradient to zonal flow velocity is homogenized. This homogenized quantity sets a constraint on the amplitudes of PV and zonal flow in the relaxed state. The second relaxation model is derived from symmetry principles alone. The form of PV flux contains a nonlinear convective term in addition to viscous and hyperviscous terms. For both cases, the transport coefficients are calculated using perturbation theory. For a broad turbulence spectrum, a modulational calculation of the PV flux gives both a negative viscosity and a positive hyperviscosity. For a narrow turbulence spectrum, the result of a parametric instability analysis shows that PV transport is also convective. In both relaxation and perturbative analyses, it is shown that turbulent PV transport is sensitive to flow structure, and the transport coefficients are nonlinear functions of flow shear.},
doi = {10.1063/1.4916401},
journal = {Physics of Plasmas},
number = 3,
volume = 22,
place = {United States},
year = 2015,
month = 3
}

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