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Large-Scale Vortex Instability in Helical Convective Turbulence

  • A. V. Tur
  • S. S. Moiseev
  • P. B. Rutkevich
  • V. V. Yanovsky
Part of the NATO ASI Series book series (NSSB, volume 237)

Abstract

Various structures that can be observed in convective flows have recently become a subject of active research (see, e.g., Westfried and Zaleski, 1984). Convection has turned into a sort of laboratory for investigation of structures and structural transitions. Here we discuss a new principal possibility typical of the turbulent convection with non-vanishing mean helicity, i.e. with non-vanishing correlation <v·∇×v> ≠ 0. We show that in turbulent convection there exists a new type of instability that leads to generation of large-scale vortex structures with non-trivial topology of streamlines (see also Moiseev et al., 1988). Such structures can be called topological solitons. Below we consider a simplified version of the problem which, however, preserves all principal physical characteristics of this phenomenon. We consider the helical turbulence created by a random external force and weak deviations from linearity in equations of motion. From physical point of view, non-zero helicity means that turbulence is non-invariant with respect to reflec-tion, i.e. the number of vortices with right-handed screwedness is not equal to the number of vortices with the left-handed one. This is the case when the random external force Fi is an axial vector.

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References

  1. Westfreid, J.E.. and Zaleski. S. (eds.), 1984. “Cellular Structures in Instabilities. Lecture Notes in Physics, v. 210”, Springer-Verlag, Berlin.Google Scholar
  2. Moiseev, S.S., Rutkevich, P.B., Tur, A.V., and Yanovskii, V.V., 1988, Vortex Dynamo in a Convective medium with Helical Turbulence. Sov. Phys. JEW, 67 (2): 294.Google Scholar
  3. Monin, A.S.. and Yaglom, A.m., 1975, “Statistical Fluid mechanics”, v. 2, Cambridge, mass., mIT Press.Google Scholar
  4. Chandrasekhar, S., 1981, “Hydrodynamic and Hydromagnetic Stability”, Dover.Google Scholar
  5. Gershuni. C.Z., and Zhukhovitskii. E.m., 1976. “Convective Stability of Incompressible Fluids”, keter PublishingHouse, Jerusalem.Google Scholar

Copyright information

© Plenum Press, New York 1990

Authors and Affiliations

  • A. V. Tur
    • 1
  • S. S. Moiseev
    • 1
  • P. B. Rutkevich
    • 1
  • V. V. Yanovsky
    • 1
  1. 1.Space Research InstituteAcademy of SciencesMoscowUSSR

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