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Papers

Alignment of velocity and vorticity and the intermittent distribution of helicity in isotropic turbulence

https://doi.org/10.1103/PhysRevE.80.017301


We provide an observation suggesting a strong correlation between helicity and enstrophy in fluid turbulence.
Helicity statistics were obtained in a direct numerical simulation of forced isotropic turbulence. An
investigation of coherent structures revealed that intermittently large local helicity was found in the core region
of the coherent rotational structures, thus showing a strong correlation with local enstrophy, not dissipation.
Statistics regarding the relative helicity and the correlation between velocity and vorticity conditioned on
different levels of enstrophy clearly suggest that velocity and vorticity tend to be aligned in the core of the
coherent structures.?


We provide an observation suggesting a strong correlation between helicity and enstrophy in fluid turbulence.
Helicity statistics were obtained in a direct numerical simulation of forced isotropic turbulence. An
investigation of coherent structures revealed that intermittently large local helicity was found in the core region
of the coherent rotational structures, thus showing a strong correlation with local enstrophy, not dissipation.
Statistics regarding the relative helicity and the correlation between velocity and vorticity conditioned on
different levels of enstrophy clearly suggest that velocity and vorticity tend to be aligned in the core of the
coherent structures.?