Two-dimensional resonant triad interactions in a two-layer system

2020 ◽  
Vol 907 ◽  
Author(s):  
Wooyoung Choi ◽  
Malik Chabane ◽  
Tore Magnus A. Taklo
Keyword(s):  
Two Dimensional ◽  
Layer System ◽  
Triad Interactions

Abstract

The Anderson transition

1975 ◽  
Vol 345 (1641) ◽  
pp. 169-205 ◽  
Keyword(s):  
Electrical Properties ◽  
Fermi Energy ◽  
Inversion Layer ◽  
Two Dimensional ◽  
Layer System ◽  
Metal Insulator Transition ◽  
Mobility Edge ◽  
Metal Insulator ◽  
Anderson Transition ◽  
Extended States

An outline is given of the electrical properties expected in a disordered solid or fluid which shows a metal-insulator transition of Anderson type. This is one in which the Fermi energy of the electrons passes through a mobility edge separating extended states from states localized by disorder, as the composition or some other parameter is changed. Some of the experimental evidence for this kind of transition is described. In particular, a relatively detailed account is given of the two dimensional inversion layer system in which the relevant parameters may be varied in a single device by direct electrical means.

On energy and enstrophy exchanges in two-dimensional non-divergent flow

1975 ◽  
Vol 69 (4) ◽  
pp. 625-630 ◽  
Author(s):  
Philip E. Merilees ◽  
Helen Warn
Keyword(s):  
Two Dimensional ◽  
Bounded Region ◽  
Divergent Flow ◽  
Triad Interactions

It is shown that, in two-dimensional non-divergent flow in a bounded region, roughly 70% of triad interactions exchange more energy with longer wavelengths than with shorter wavelengths whilst roughly 40% exchange more enstrophy with longer wavelengths than with shorter wavelengths.

Steady Rayleigh–Be´nard Convection in a Two-Layer System of Immiscible Liquids

1996 ◽  
Vol 118 (2) ◽  
pp. 366-373 ◽  
Author(s):  
A. Prakash ◽  
J. N. Koster
Keyword(s):  
Numerical Simulations ◽  
Thermal Convection ◽  
Reasonable Agreement ◽  
Two Dimensional ◽  
Thermal Coupling ◽  
Layer System ◽  
Immiscible Liquids ◽  
Mechanical Coupling ◽  
Buoyancy Forces ◽  
Coupling Mode

Two-dimensional thermal convection in a system of two immiscible liquids heated from below is studied experimentally and numerically. Convection in the two-layer system is characterized by two distinct coupling modes between the layers. They are mechanical coupling and thermal coupling. These two coupling modes are visualized experimentally and found to be in reasonable agreement with numerical simulations. When buoyancy forces in both layers are of similar strength, thermal coupling is preferred. The mechanical coupling mode dominates when the buoyancy forces are very different in both layers.

Note on the triad interactions of homogeneous turbulence

2014 ◽  
Vol 741 ◽  
Author(s):  
H. K. Moffatt
Keyword(s):  
Linear Problem ◽  
Flow Problem ◽  
Initial Conditions ◽  
Passive Scalar ◽  
Two Dimensional ◽  
Vorticity Field ◽  
Marked Contrast ◽  
Scalar Type ◽  
Two Dimensional Flow ◽  
Triad Interactions

AbstractTriad interactions, involving a set of wave-vectors $\{\pm \boldsymbol {k}, \pm \boldsymbol {p}, \pm \boldsymbol {q}\}$, with $ \boldsymbol {k} + \boldsymbol {p}+ \boldsymbol {q}=0$, are considered, and the results of triad truncation are compared with the results of exact Euler evolution starting from the same initial conditions. The essential two-dimensionality of the triad interaction is used to separate the problem into two parts: a nonlinear two-dimensional flow problem in the triad plane, and a linear problem of ‘passive scalar’ type for the evolution of the component of velocity perpendicular to this plane. Several examples of triad evolution are presented in detail, and the marked contrast with Euler evolution is demonstrated. It is known that energy and helicity are conserved under triad truncation; it is shown that the ‘in-plane’ energy and enstrophy are also conserved. However, it is also shown that, in general, the evolution of the vorticity under triad truncation cannot be represented as transport by any divergence-free velocity field, with the consequence that the detailed topology of the vorticity field is not conserved under this truncation.

scholarly journals Well-posedness in Sobolev spaces of the two-dimensional MHD boundary layer equations without viscosity

2021 ◽  
Vol 0 (0) ◽  
pp. 0
Author(s):  
Wei-Xi Li ◽  
Rui Xu
Keyword(s):  
Boundary Layer ◽  
Sobolev Spaces ◽  
Tangential Component ◽  
Well Posedness ◽  
Two Dimensional ◽  
Uniqueness Of Solutions ◽  
Layer System ◽  
Boundary Layer Equations ◽  
Mhd Boundary Layer ◽  
Liu Xie

<p style='text-indent:20px;'>We consider the two-dimensional MHD Boundary layer system without hydrodynamic viscosity, and establish the existence and uniqueness of solutions in Sobolev spaces under the assumption that the tangential component of magnetic fields dominates. This gives a complement to the previous works of Liu-Xie-Yang [Comm. Pure Appl. Math. 72 (2019)] and Liu-Wang-Xie-Yang [J. Funct. Anal. 279 (2020)], where the well-posedness theory was established for the MHD boundary layer systems with both viscosity and resistivity and with viscosity only, respectively. We use the pseudo-differential calculation, to overcome a new difficulty arising from the treatment of boundary integrals due to the absence of the diffusion property for the velocity.</p>

Spectrophotometric measurements of objective-prism spectra

1966 ◽  
Vol 24 ◽  
pp. 118-119
Author(s):  
Th. Schmidt-Kaler
Keyword(s):  
Progress Report ◽  
Two Dimensional ◽  
Objective Prism ◽  
Made In

I should like to give you a very condensed progress report on some spectrophotometric measurements of objective-prism spectra made in collaboration with H. Leicher at Bonn. The procedure used is almost completely automatic. The measurements are made with the help of a semi-automatic fully digitized registering microphotometer constructed by Hög-Hamburg. The reductions are carried out with the aid of a number of interconnected programmes written for the computer IBM 7090, beginning with the output of the photometer in the form of punched cards and ending with the printing-out of the final two-dimensional classifications.

Introductory paper

1966 ◽  
Vol 24 ◽  
pp. 3-5
Author(s):  
W. W. Morgan
Keyword(s):  
Line Intensity ◽  
Classification Scheme ◽  
Two Dimensional ◽  
Spectral Classification ◽  
Dimensional Array ◽  
Rr Lyrae ◽  
Metallic Line ◽  
Introductory Paper ◽  
Parameter Varying ◽  
Definition Of

1. The definition of “normal” stars in spectral classification changes with time; at the time of the publication of theYerkes Spectral Atlasthe term “normal” was applied to stars whose spectra could be fitted smoothly into a two-dimensional array. Thus, at that time, weak-lined spectra (RR Lyrae and HD 140283) would have been considered peculiar. At the present time we would tend to classify such spectra as “normal”—in a more complicated classification scheme which would have a parameter varying with metallic-line intensity within a specific spectral subdivision.

A one-dimensional self-gravitating stellar gas

1966 ◽  
Vol 25 ◽  
pp. 46-48 ◽  
Author(s):  
M. Lecar
Keyword(s):  
Gravitational Field ◽  
Phase Space ◽  
Motion Picture ◽  
Space Distribution ◽  
Two Dimensional ◽  
One Dimensional ◽  
Phase Space Distribution ◽  
Dimensional Phase Space ◽  
The Mean

“Dynamical mixing”, i.e. relaxation of a stellar phase space distribution through interaction with the mean gravitational field, is numerically investigated for a one-dimensional self-gravitating stellar gas. Qualitative results are presented in the form of a motion picture of the flow of phase points (representing homogeneous slabs of stars) in two-dimensional phase space.

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