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Physics of Fluids / Volume 12 / Issue 5 / ARTICLES

Phys. Fluids 12, 1166 (2000); http://dx.doi.org/10.1063/1.870369 (23 pages)

Interaction of vorticity, rate-of-strain, and scalar gradient in stratified homogeneous sheared turbulence

P. J. Diamessis and K. K. Nomura

Department of Mechanical and Aerospace Engineering, University of California at San Diego, La Jolla, California 92093-0411

(Received 20 October 1999; accepted 25 January 2000)

The structure and dynamics of stably stratified homogeneous sheared turbulence is investigated in terms of the triadic interaction of vorticity ω, rate-of-strain S, and scalar (density fluctuation) gradient G ≡ ∇ρ′. Results of direct numerical simulations are presented. Due to the presence of the mean velocity and scalar gradients, distinct directional preferences develop which affect the dynamics of the flow. The triadic interaction is described in terms of the direct coupling of primary mechanism pairs and influential secondary effects. Interaction of ω and S is characterized by the coupling of vortex stretching and locally-induced rotation of the S axes. Due to the intrinsic directionality of baroclinic torque, the generated ω acts to impede S axes rotation. Interaction of ω and G involves an inherent negative feedback between baroclinic torque and reorientation of G by ω. This causes baroclinic torque to act as a sink which promotes decay of ω2. Interaction of S and G is characterized by a positive feedback between differential acceleration and gradient amplification by compressive straining which promotes persistence in vertical G. In high-amplitude, rotation-dominated regions of the flow, differential acceleration effects enhance the attenuation of vertical ω while shear and baroclinic torque tend to maintain horizontal ω. This leads to a predominance of horizontal ω in these regions which manifests itself as collapsed vortex structures. As the flow develops, the third invariant of the velocity gradient tensor tends towards zero indicating locally two-dimensional flow. © 2000 American Institute of Physics.

© 2000 American Institute of Physics

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KEYWORDS and PACS

Keywords

shear turbulence, stratified flow, vortices, flow simulation

PACS

ARTICLE DATA

Digital Object Identifier
http://dx.doi.org/10.1063/1.870369

PUBLICATION DATA

ISSN

1070-6631 (print)  
1089-7666 (online)

Publisher

$abstract.society.value is a Member of CrossRef American Institute of Physics

For access to fully linked references, you need to log in.
    W. T. Ashurst, A. R. Kerstein, R. M. Kerr, and C. H. Gibson, "Alignment of vorticity and scalar gradient with strain rate in simulated Navier–Stokes turbulence," Phys. Fluids 30, 2343 (1987)PFLDAS000030000008002343000001.

    G. R. Ruetsch and M. R. Maxey, "Small-scale features of vorticity and passive scalar fields in homogeneous isotropic turbulence," Phys. Fluids A 3, 1587 (1991)PFADEB000003000006001587000001.

    K. K. Nomura and S. E. Elghobashi, "Mixing characteristics of an inhomogeneous scalar in isotropic and homogeneous sheared turbulence," Phys. Fluids 4, 606 (1992)PFADEB000004000003000606000001.

    S. Douady, Y. Couder, and M. E. Brachet, "Direct observation of the intermittency of intense vorticity filaments in turbulence," Phys. Rev. Lett. 67, 983 (1991).

    M. Tanaka and S. Kida, "Characterization of vortex tubes and sheets," Phys. Fluids A 5, 2079 (1993)PFADEB000005000009002079000001.

    E. Villermaux, B. Sixon, and Y. Gagne, "Intense vortical structures in grid-generated turbulence," Phys. Fluids 7, 2008 (1995)PHFLE6000007000008002008000001.

    T. Gerz, J. Howell, and L. Mahrt, "Vortex structures and microfronts," Phys. Fluids 6, 1242 (1994)PHFLE6000006000003001242000001.

    K. K. Nomura and P. J. Diamessis, "The interaction of vorticity and rate of strain in homogeneous sheared turbulence," Phys. Fluids 12, 846 (2000)PHFLE6000012000004000846000001.

    A. Majda and M. J. Grote, "Model dynamics and vertical collapse in decaying strongly stratified flows," Phys. Fluids 9, 2932 (1997)PHFLE6000009000010002932000001.

    B. J. Cantwell, "On the behavior of velocity gradient tensor invariants in direct numerical simulations of turbulence," Phys. Fluids A 5, 2008 (1993)PFADEB000005000008002008000001.


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