Anisotropic macroturbulence and diffusion associated with a westward zonal jet: From laboratory to planetary atmospheres and oceans
| Autor: | Galperin, Boris, Hoemann, Jesse, Espa, Stefania, Di Nitto, Gabriella, Lacorata, Guglielmo |
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| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
statistics and probability
010504 meteorology & atmospheric sciences statistical and nonlinear physics Lyapunov exponent Finite-Scale Lyapunov Exponents condensed matter physics Thermal diffusivity 01 natural sciences Zonal Jet 010305 fluids & plasmas Eddy diffusion Physics::Fluid Dynamics symbols.namesake Potential vorticity 0103 physical sciences Diffusion (business) Physics::Atmospheric and Oceanic Physics 0105 earth and related environmental sciences Relative Dispersion Physics Jet (fluid) Turbulence Mechanics Classical mechanics Energy cascade Experimental Fluid Dynamics symbols Macroturbulence |
| Zdroj: | Physical review. E, Statistical, nonlinear, and soft matter physics 94 (2016): 063102. doi:10.1103/PhysRevE.94.063102 info:cnr-pdr/source/autori:Galperin, Boris and Hoemann, Jesse and Espa, Stefania and Di Nitto, Gabriella and Lacorata, Guglielmo/titolo:Anisotropic macroturbulence and diffusion associated with a westward zonal jet: From laboratory to planetary atmospheres and oceans/doi:10.1103%2FPhysRevE.94.063102/rivista:Physical review. E, Statistical, nonlinear, and soft matter physics (Print)/anno:2016/pagina_da:/pagina_a:063102/intervallo_pagine:063102/volume:94 |
| DOI: | 10.1103/PhysRevE.94.063102 |
| Popis: | Turbulence with inverse energy cascade and its transport properties are investigated experimentally in a flow associated with a westward propagating jet. Turbulence and the jet were produced by an electromagnetic force in a rotating tank filled with an electrolytic saline solution. The parabolic free surface emulated the topographic $\ensuremath{\beta}$ effect which evoked the zonation. The spectral and transport flow characteristics were highly anisotropic. Turbulence is diagnosed by exploring the analogy between vertical and horizontal turbulent overturns in, respectively, stably stratified and quasigeostrophic flows which gives rise to a method of potential vorticity (PV) monotonizing. The anisotropization of transport properties of the flow is investigated using the finite scale Lyapunov exponent technique. After initial exponential particle separation, radial (meridional in geophysical and planetary applications) diffusion attains a short-ranged Richardson regime which transitions to the Taylor (scale-independent diffusivity) one. The azimuthal (zonal) diffusion exhibits a double-plateau structure which attains a superdiffusive regime on large scales. The transition to the Taylor regime for the radial diffusion takes place at a scale of turbulence anisotropization. The radial eddy diffusivity in both regimes as well as the transition scale are all determined by the rate of the inverse energy cascade, $\ensuremath{\epsilon}$, that can be diagnosed by the PV monotonizing. Conversely, $\ensuremath{\epsilon}$ can be deduced from the scale of the Richardson-Taylor regime transition in the radial eddy diffusivity which, thus, provides an additional tool of diagnosing anisotropic macroturbulence with inverse energy cascade. |
| Databáze: | OpenAIRE |
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