The realizable Markovian closure and realizable test-field model. II. Application to anisotropic drift-wave dynamics

1997 ◽  
Vol 4 (11) ◽  
pp. 3895-3909 ◽  
Author(s):  
John C. Bowman ◽  
John A. Krommes
Keyword(s):  
Field Model ◽  
Test Field ◽  
Wave Dynamics ◽  
Drift Wave

scholarly journals Blobs and drift wave dynamics

2017 ◽  
Vol 24 (9) ◽  
pp. 092313 ◽  
Author(s):  
Yanzeng Zhang ◽  
S. I. Krasheninnikov
Keyword(s):  
Wave Dynamics ◽  
Drift Wave

Resonant-test-field model of fluctuating nonlinear waves

1982 ◽  
Vol 25 (3) ◽  
pp. 1683-1691 ◽  
Author(s):  
Bruce J. West
Keyword(s):  
Nonlinear Waves ◽  
Field Model ◽  
Test Field

Selective decay within a one‐field model of dissipative drift‐wave turbulence

1992 ◽  
Vol 4 (8) ◽  
pp. 2672-2674 ◽  
Author(s):  
V. Naulin ◽  
K. H. Spatschek ◽  
A. Hasegawa
Keyword(s):  
Field Model ◽  
Wave Turbulence ◽  
Drift Wave Turbulence ◽  
Drift Wave ◽  
Selective Decay

Test-field model for inhomogeneous turbulence

1972 ◽  
Vol 56 (2) ◽  
pp. 287-304 ◽  
Author(s):  
Robert H. Kraichnan
Keyword(s):  
Field Model ◽  
Isotropic Turbulence ◽  
Direct Interaction ◽  
Test Field ◽  
Dynamical Equations ◽  
Numerical Work ◽  
Variance Matrix ◽  
Numerical Predictions ◽  
Inhomogeneous Turbulence ◽  
Starting Point

The test-field model for isotropic turbulence is restated in a form which is independent of the choice of orthogonal basis functions for representing the velocity field. The model is then extended to non-stationary inhomogeneous turbulence with a mean shearing velocity, contained by boundaries of arbitrary shape. A modification of the model is introduced which makes negligible changes in the numerical predictions but which greatly simplifies computations when the co-variance matrix and related statistical matrices are non-diagonal. The altered model may be regarded as a kind of generalization of Orszag's eddy-damped Markovian model, with the damping factors determined systematically, in representation-independent form, from dynamical equations. The final equations of the test-field model are presented in a sufficiently explicit form to serve as a starting point for numerical work. To facilitate comparison, the corresponding direct-interaction equations for inhomogeneous turbulence with mean shear are presented also, in a uniform notation. The test-field model is much faster to compute than the direct-interaction approximation because, in the former, only single-time statistical functions need be computed. This advantage is at the cost of a less rich and less faithful representation of the dynamics.

Spectral transfer in a two-field model of drift wave turbulence

1995 ◽  
Vol 52 (5) ◽  
pp. 561-564 ◽  
Author(s):  
Alireza Pakyari ◽  
Vladimir P Pavlenko
Keyword(s):  
Field Model ◽  
Wave Turbulence ◽  
Drift Wave Turbulence ◽  
Drift Wave

scholarly journals Dynamics of Periodic Waves in a Neural Field Model

2020 ◽  
Author(s):  
Nikolai Bessonov ◽  
Anne Beuter ◽  
Sergei Trofimchuk ◽  
Vitaly Volpert
Keyword(s):  
Time Delay ◽  
Field Model ◽  
Travelling Waves ◽  
Neural Field ◽  
Nonlocal Interaction ◽  
Periodic Waves ◽  
External Stimulation ◽  
Wave Dynamics ◽  
Neural Field Model ◽  
Visual Motor

Periodic travelling waves are observed in various brain activities including visual, motor, language, sleep, and so on. There are several neural field models describing periodic waves assuming nonlocal interaction and, possibly, inhibition, time delay, or some other properties. In this work we study the influence of asymmetric connectivity functions and of time delay on the emergence of periodic waves and on their properties. Nonlinear wave dynamics is studied, including modulated and aperiodic waves. Multiplicity of waves for the same values of parameters is observed. External stimulation in order to restore wave propagation in a damaged tissue is discussed.

Decay of two-dimensional homogeneous turbulence

1974 ◽  
Vol 66 (3) ◽  
pp. 417-444 ◽  
Author(s):  
J. R. Herring ◽  
S. A. Orszag ◽  
R. H. Kraichnan ◽  
D. G. Fox
Keyword(s):  
Large Scale ◽  
Field Model ◽  
Grid Point ◽  
Finite Difference Methods ◽  
Direct Interaction ◽  
Reynolds Numbers ◽  
Test Field ◽  
Two Dimensional ◽  
Direct Interaction Approximation ◽  
Interaction Approximation

The decay of two-dimensional, homogeneous, isotropic, incompressible turbulence is investigated both by means of numerical simulation (in spectral as well as in grid-point form), and theoretically by use of the direct-interaction approximation and the test-field model. The calculations cover the range of Reynolds numbers 50 ≤ RL ≤ 100. Comparison of spectral methods with finite-difference methods shows that one of the former with a given resolution is equivalent in accuracy to one of the latter with twice the resolution. The numerical simulations at the larger Reynolds numbers suggest that earlier reported simulations cannot be used in testing inertial-range theories. However, the large-scale features of the flow field appear to be remarkably independent of Reynolds number.The direct-interaction approximation is in satisfactory agreement with simulations in the energy-containing range, but grossly underestimates enstrophy transfer at high wavenumbers. The latter failing is traced to an inability to distinguish between convection and intrinsic distortion of small parcels of fluid. The test-field model on the other hand appears to be in excellent agreement with simulations at all wavenumbers, and for all Reynolds numbers investigated.

scholarly journals Blobs in the framework of drift wave dynamics

2016 ◽  
Vol 23 (12) ◽  
pp. 124501 ◽  
Author(s):  
Yanzeng Zhang ◽  
S. I. Krasheninnikov
Keyword(s):  
Wave Dynamics ◽  
Drift Wave

scholarly journals Dynamics of Periodic Waves in a Neural Field Model

Mathematics ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 1076
Author(s):  
Nikolai Bessonov ◽  
Anne Beuter ◽  
Sergei Trofimchuk ◽  
Vitaly Volpert
Keyword(s):  
Time Delay ◽  
Field Model ◽  
Neural Field ◽  
Nonlocal Interaction ◽  
Periodic Waves ◽  
External Stimulation ◽  
Wave Dynamics ◽  
Periodic Traveling Waves ◽  
Neural Field Model ◽  
Visual Motor

Periodic traveling waves are observed in various brain activities, including visual, motor, language, sleep, and so on. There are several neural field models describing periodic waves assuming nonlocal interaction, and possibly, inhibition, time delay or some other properties. In this work we study the influences of asymmetric connectivity functions and of time delay for symmetric connectivity functions on the emergence of periodic waves and their properties. Nonlinear wave dynamics are studied, including modulated and aperiodic waves. Multiplicity of waves for the same values of parameters is observed. External stimulation in order to restore wave propagation in a damaged tissue is discussed.

Statistical mechanics of a two‐field model of drift wave turbulence

1989 ◽  
Vol 1 (6) ◽  
pp. 1331-1333 ◽  
Author(s):  
F. Y. Gang ◽  
B. D. Scott ◽  
P. H. Diamond
Keyword(s):  
Statistical Mechanics ◽  
Field Model ◽  
Wave Turbulence ◽  
Drift Wave Turbulence ◽  
Drift Wave
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