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

Phys Rev E Stat Nonlin Soft Matter Phys

Department of Mechanical Engineering, Yonsei University, Seodaemun-gu, Seoul 120-749, Korea.

Published: July 2009

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.

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http://dx.doi.org/10.1103/PhysRevE.80.017301DOI Listing

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