Display options
Cite
Kessar M, Plunian F, Stepanov R, et al. Non-Kolmogorov cascade of helicity-driven turbulence. Phys Rev E Stat Nonlin Soft Matter Phys. 2015;92(3):031004doi: 10.1103/PhysRevE.92.031004.
Kessar, M., Plunian, F., Stepanov, R., & Balarac, G. (2015). Non-Kolmogorov cascade of helicity-driven turbulence. Physical review. E, Statistical, nonlinear, and soft matter physics, 92(3), 031004. https://doi.org/10.1103/PhysRevE.92.031004
Kessar, Mouloud, et al. "Non-Kolmogorov cascade of helicity-driven turbulence." Physical review. E, Statistical, nonlinear, and soft matter physics vol. 92,3 (2015): 031004. doi: https://doi.org/10.1103/PhysRevE.92.031004
Kessar M, Plunian F, Stepanov R, Balarac G. Non-Kolmogorov cascade of helicity-driven turbulence. Phys Rev E Stat Nonlin Soft Matter Phys. 2015 Sep;92(3):031004. doi: 10.1103/PhysRevE.92.031004. Epub 2015 Sep 28. PMID: 26465417.
Copy Download .nbib Format: NLM
Share it on

Phys Rev E Stat Nonlin Soft Matter Phys. 2015 Sep;92(3):031004. doi: 10.1103/PhysRevE.92.031004. Epub 2015 Sep 28.

Non-Kolmogorov cascade of helicity-driven turbulence.

Physical review. E, Statistical, nonlinear, and soft matter physics

Mouloud Kessar, Franck Plunian, Rodion Stepanov, Guillaume Balarac

Affiliations

  1. Université Grenoble Alpes, CNRS, LEGI, Grenoble, France.
  2. Université Grenoble Alpes, CNRS, ISTerre, Grenoble, France.
  3. Institute of Continuous Media Mechanics, Korolyov str. 1, 614013 Perm, Russia.
  4. Perm National Research Polytechnic University, Komsomolskii av. 29, 614990 Perm, Russia.

PMID: 26465417 DOI: 10.1103/PhysRevE.92.031004

Abstract

We solve the Navier-Stokes equations with two simultaneous forcings. One forcing is applied at a given large scale and it injects energy. The other forcing is applied at all scales belonging to the inertial range and it injects helicity. In this way we can vary the degree of turbulence helicity from nonhelical to maximally helical. We find that increasing the rate of helicity injection does not change the energy flux. On the other hand, the level of total energy is strongly increased and the energy spectrum gets steeper. The energy spectrum spans from a Kolmogorov scaling law k^{-5/3} for a nonhelical turbulence, to a non-Kolmogorov scaling law k^{-7/3} for a maximally helical turbulence. In the latter case we find that the characteristic time of the turbulence is not the turnover time but a time based on the helicity injection rate. We also analyze the results in terms of helical modes decomposition. For a maximally helical turbulence one type of helical mode is found to be much more energetic than the other one, by several orders of magnitude. The energy cascade of the most energetic type of helical mode results from the sum of two fluxes. One flux is negative and can be understood in terms of a decimated model. This negative flux, however, is not sufficient to lead an inverse energy cascade. Indeed, the other flux involving the least energetic type of helical mode is positive and the largest. The least energetic type of helical mode is then essential and cannot be neglected.

Publication Types