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Large scale dissipation and filament instability in two-dimensional turbulence.
Dalila Elhmaidi1, Jost von Hardenberg, Antonello Provenzale
1Laboratoire de Mécanique des Fluides, Faculté des Sciences de Tunis, Tunisia.
Physical Review Letters
|August 11, 2005
Summary
Large-scale energy sinks in two-dimensional turbulence simulations unexpectedly destabilize vorticity filaments, promoting continuous vortex formation. This finding impacts understanding of vortex dynamics in forced and decaying turbulence.
Area of Science:
- Fluid Dynamics
- Turbulence Theory
- Computational Physics
Background:
- Coherent vortices in 2D turbulence stabilize filaments, inhibiting new vortex generation.
- Numerical simulations often include large-scale energy sinks for statistical stationarity.
Purpose of the Study:
- Investigate the effect of large-scale energy sinks on vortex dynamics in 2D turbulence.
- Clarify mechanisms of vortex formation in forced-dissipated 2D turbulence.
- Analyze the impact on vortex population evolution in decaying turbulence.
Main Methods:
- Numerical simulations of statistically stationary 2D turbulence.
- Analysis of vortex statistics and filament stability.
- Comparison with existing scaling theories.
Main Results:
- Large-scale energy sinks reduce the stabilizing influence of coherent vortices.
- This reduction leads to filament instability and continuous new vortex generation.
- The temporal evolution of vortex statistics with energy sinks can be approximated by modified scaling theory.
Conclusions:
- Energy sinks have a counterintuitive destabilizing effect on vortex filaments in 2D turbulence.
- This challenges previous assumptions about vortex formation mechanisms.
- The study provides insights into vortex population dynamics in various turbulence regimes.