201. Kinetic helicity decay in linearly forced turbulence
- Author
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Brandenburg, Axel and Petrosyan, Arakel
- Subjects
Astrophysics - Solar and Stellar Astrophysics ,Nonlinear Sciences - Chaotic Dynamics ,Physics - Atmospheric and Oceanic Physics ,Physics - Fluid Dynamics ,Physics - Space Physics - Abstract
The decay of kinetic helicity is studied in numerical models of forced turbulence using either an externally imposed forcing function as an inhomogeneous term in the equations or, alternatively, a term linear in the velocity giving rise to a linear instability. The externally imposed forcing function injects energy at the largest scales, giving rise to a turbulent inertial range with nearly constant energy flux while for linearly forced turbulence the spectral energy is maximum near the dissipation wavenumber. Kinetic helicity is injected once a statistically steady state is reached, but it is found to decay on a turbulent time scale regardless of the nature of the forcing and the value of the Reynolds number., Comment: 7 pages, 8 figures, Astron. Nachr. (accepted)
- Published
- 2010
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