Asymmetric flows in planar symmetric channels with large expansion ratio

Sanjay Mishra, K. Jayaraman

    Research output: Research - peer-reviewArticle

    • 19 Citations

    Abstract

    A continuation method has been used with a finite element grid and a geometric perturbation to compute two successive symmetry breaking flow transitions with increasing Reynolds number in flow of generalized Newtonian fluids through a sudden planar expansion. With an expansion ratio of 16, the onset Reynolds number is particularly sensitive to small geometric asymmetry and the critical Reynolds numbers for the two successive flow transitions are found to be very close. These transitions are delayed to higher onset Reynolds numbers by increasing the degree of pseudoplasticity. This trend is observed experimentally as well in this work and may be attributed to the competing effects of shear thinning and inertia on the size of the corner vortex before the symmetry breaking flow transition. After the second transition with an expansion ratio of 16, the two large staggered vortices on opposite walls occupy most of the transverse dimension so that the core flow between the vortices appears as a thin jet oscillating along the flow direction. This is more pronounced for the pseudoplastic liquid. After the second transition, the degree of flow asymmetry at a given location downstream of the expansion plane is larger for the pseudoplastic liquid than for the Newtonian liquid at comparable Reynolds numbers. The last feature is also evident in the experimentally observed velocity profiles.

    LanguageEnglish (US)
    Pages945-962
    Number of pages18
    JournalInternational Journal for Numerical Methods in Fluids
    Volume38
    Issue number10
    DOIs
    StatePublished - Apr 10 2002

    Profile

    Reynolds number
    expansion
    transition flow
    vortices
    liquids
    Transition flow
    Vortex flow
    broken symmetry
    asymmetry
    Vortex
    Liquid
    Liquids
    Symmetry Breaking
    Asymmetry
    core flow
    shear thinning
    Newtonian fluids
    high Reynolds number
    inertia
    velocity distribution

    Keywords

    • Asymmetric flow
    • Bifurcation
    • Instability
    • Sudden expansion
    • Transition

    ASJC Scopus subject areas

    • Condensed Matter Physics
    • Safety, Risk, Reliability and Quality
    • Applied Mathematics
    • Computational Theory and Mathematics
    • Computer Science Applications
    • Computational Mechanics
    • Mechanics of Materials

    Cite this

    Asymmetric flows in planar symmetric channels with large expansion ratio. / Mishra, Sanjay; Jayaraman, K.

    In: International Journal for Numerical Methods in Fluids, Vol. 38, No. 10, 10.04.2002, p. 945-962.

    Research output: Research - peer-reviewArticle

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