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Interacting scales and triad enstrophy transfers in generalized two-dimensional turbulence
Takeshi Watanabe1, Takahiro Iwayama
1Department of Engineering Physics, Nagoya Institute of Technology, Gokiso, Showa-ku, Nagoya 466-8555, Japan. watanabe@nitech.ac.jp
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|November 13, 2007
Summary
Nonlocal triad interactions dominate enstrophy transfer in alpha turbulence. Local interactions become more significant as alpha decreases, particularly in surface quasigeostrophic turbulence (alpha=1).
Area of Science:
- Fluid Dynamics
- Turbulence Theory
- Computational Physics
Background:
- Generalized two-dimensional turbulence, or alpha turbulence, exhibits an enstrophy inertial range.
- Understanding enstrophy transfer mechanisms is crucial for characterizing turbulent flows.
Purpose of the Study:
- Investigate the local and nonlocal characteristics of triad enstrophy transfer in alpha turbulence.
- Analyze the influence of the alpha parameter on enstrophy transfer dynamics.
Main Methods:
- Direct numerical simulations were employed to study alpha turbulence.
- Simulations focused on specific alpha values: 1, 2, and 3.
Main Results:
- Nonlocal triad interactions were found to dominate enstrophy transfer across the enstrophy inertial range for all alpha values.
- The contribution of local interactions to total enstrophy transfer increases as alpha decreases.
- A transition in enstrophy transfer from nonlocal to more local characteristics was observed as alpha decreases, aligning with theoretical predictions.
Conclusions:
- Nonlocal interactions are the primary driver of enstrophy transfer in alpha turbulence.
- The degree of locality in enstrophy transfer is sensitive to the alpha parameter.
- Specific behaviors, like those in surface quasigeostrophic turbulence (alpha=1), highlight the nuanced nature of enstrophy transfer in different regimes.
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