Artículo

La versión final de este artículo es de uso interno de la institución.
Consulte el artículo en la página del editor
Consulte la política de Acceso Abierto del editor

Abstract:

Helicity is a quadratic invariant of the Euler equation in three dimensions. As the energy, when present helicity cascades to smaller scales where it dissipates. However, the role played by helicity in the energy cascade is still unclear. In non-helical flows, the velocity and the vorticity tend to align locally creating patches with opposite signs of helicity. Also in helical flows helicity changes sign rapidly in space. Not being a positive definite quantity, global studies considering its spectral scaling in the inertial range are inconclusive, except for cases where one sign of helicity is dominant. We use the cancellation exponent to characterize the scaling laws followed by helicity fluctuations in numerical simulations of helical and non-helical turbulent flows, with different forcing functions and spanning a range of Reynolds numbers from ≈ 670 to ≈ 6200. The exponent can be related to the fractal dimension as well as to the first-order helicity scaling exponent. The results are consistent with the geometry of helical structures being filamentary. Further analysis indicates that statistical properties of helicity fluctuations in the simulations do not depend on the global helicity of the flow. © 2010 Cambridge University Press.

Registro:

Documento: Artículo
Título:Cancellation exponents in helical and non-helical flows
Autor:Imazio, P.R.; Mininni, P.D.
Filiación:Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires 1428, Argentina
National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307, United States
Palabras clave:Energy cascade; First-order; Forcing function; Helical flows; Helical structures; Helicities; Helicity cascades; Numerical simulation; Positive definite; Quadratic invariant; Scaling exponent; Statistical properties; Three dimensions; Computer simulation; Euler equations; Reynolds number; Fractal dimension; Eulerian analysis; flow velocity; numerical model; Reynolds number; turbulent flow; vorticity
Año:2010
Volumen:651
Página de inicio:241
Página de fin:250
DOI: http://dx.doi.org/10.1017/S0022112010000819
Título revista:Journal of Fluid Mechanics
Título revista abreviado:J. Fluid Mech.
ISSN:00221120
CODEN:JFLSA
Registro:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00221120_v651_n_p241_Imazio

Referencias:

  • Baerenzung, J., Politano, H., Ponty, Y., Pouquet, A., Spectral modelling of turbulent flows and the role of helicity (2008) Phys. Rev. E., 77, p. 046303
  • Borue, V., Orszag, S.A., Spectra in helical three-dimensional homogeneous isotropic turbulence (1997) Phys. Rev. E., 55, pp. 7005-7009
  • Brissaud, A., Frisch, U., Léorat, J., Lesieur, M., Mazure, A., Helicity cascades in fully developed isotropic turbulence (1973) Phys. Fluids, 16, pp. 1366-1367
  • Bruno, R., Carbone, V., Sign singularity of the magnetic helicity from in situ solar wind observations (1997) Astrophys. J., 488, pp. 482-487
  • Chen, Q., Chen, S., Eyink, G., The joint cascade of energy and helicity in three-dimensional turbulence (2003) Phys. Fluids., 15, pp. 361-374
  • Chen, Q., Chen, S., Eyink, G., Holm, D., Intermittency and the joint cascade of energy and helicity (2003) Phys. Rev. Lett., 90, p. 214503
  • Eyink, G., Sreenivasan, K., Onsager and the theory of hydrodinamic turbulence (2006) Rev. Mod. Phys., 78, pp. 87-134
  • Farge, M., Pellegrino, G., Schneider, K., Coherent vortex extraction in 3D turbulent flows using orthogonal wavelets (2001) Phys. Rev. Lett., 87, p. 054501
  • Frisch, U., (1995) Turbulence, , Cambridge University Press
  • Gomez, D.O., Mininni, P.D., Understanding turbulence through numerical simulations (2004) Physica A, 342, pp. 69-75
  • Holm, D., Kerr, R., Helicity in the formation of turbulence (2007) Phys. Fluids, 19, p. 025101
  • Kolmogorov, A.N., The local structure of turbulence in incompressible viscous fluid for very large Reynolds number (1941) Dokl. Acad. Nauk SSSR A, 30, pp. 301-305
  • Kurien, S., The reflection-antisymmetric counterpart of the Kármán- Howarth dynamical equation (2003) Physica D, 175, pp. 167-176
  • Lilly, D., The structure, energetics and propagation of rotating convective storms (1986) J. Atmos. Sci., 43, pp. 126-140
  • Mininni, P., Alexakis, A., Pouquet, A., Large scale flow effects, energy transfer, and self-similarity on turbulence (2006) Phys. Rev. E., 74, p. 016303
  • Moffatt, H.K., The degree of knottedness of tangled vortex lines (1969) J. Fluid Mech., 35, pp. 117-129
  • Moffat, H.K., Cambridge university press (1978) Magnetic Field Generation in Electrically Conducting Fluids
  • Moffatt, H.K., Magnetostatic equilibria and analogous Euler flows of arbitrarily complex topology (1985) J. Fluid Mech., 159, pp. 359-378
  • Moffatt, H.K., Tsinober, A., Helicity in laminar and turbulent flows (1992) Annu. Rev. Fluid Mech., 24, pp. 281-312
  • Ott, E., Du, Y., Sreenivasan, K., Juneja, A., Suri, A., Sign-singular measures: Fast magnetic dynamos, and high-Reynolds-number fluid turbulence (1992) Phys. Rev. Lett., 69, pp. 2654-2657
  • Pietarila Graham, J., Mininni, P.D., Pouquet, A., Cancellation exponent and multifractal structure in two-dimensional magnetohydrodynamics: Direct numerical simulations and Lagrangian averaged modelling (2005) Phys. Rev. E., 72, pp. 045301R
  • Pope, S., (2000) Turbulent Flows, , Cambridge University Press
  • Pouquet, A., Frisch, U., Léorat, J., Strong MHD helical turbulence and the nonlinear dynamo effect (1976) J. Fluid Mech., 77, pp. 321-354
  • Sorriso-Valvo, L., Carbone, B., Noullez, A., Politano, H., Pouquet, A., Veltri, P., Analisys of cancellation in two-dimensional magnetohydrodinamic turbulence (2002) Phys. Plasmas, 9, pp. 89-95
  • Vainshtein, S.I., Sreenivasan, K.R., Pierrehumbert, R.T., Kashyap, V., Juneja, A., Scaling exponents for turbulence and other random processes and their relationships with multifractal structure (1994) Phys. Rev. E., 50, pp. 1823-1835
  • Wilkin, L.S., Barenghi, C.F., Shukurov, A., Magnetic structures produced by small-scale dynamos (2007) Phys. Rev. Lett., 99, p. 134501

Citas:

---------- APA ----------
Imazio, P.R. & Mininni, P.D. (2010) . Cancellation exponents in helical and non-helical flows. Journal of Fluid Mechanics, 651, 241-250.
http://dx.doi.org/10.1017/S0022112010000819
---------- CHICAGO ----------
Imazio, P.R., Mininni, P.D. "Cancellation exponents in helical and non-helical flows" . Journal of Fluid Mechanics 651 (2010) : 241-250.
http://dx.doi.org/10.1017/S0022112010000819
---------- MLA ----------
Imazio, P.R., Mininni, P.D. "Cancellation exponents in helical and non-helical flows" . Journal of Fluid Mechanics, vol. 651, 2010, pp. 241-250.
http://dx.doi.org/10.1017/S0022112010000819
---------- VANCOUVER ----------
Imazio, P.R., Mininni, P.D. Cancellation exponents in helical and non-helical flows. J. Fluid Mech. 2010;651:241-250.
http://dx.doi.org/10.1017/S0022112010000819