Mixing in Circular and Non-circular Jets in Crossflow

Mirko Salewski, D. Stankovic, L. Fuchs

    Research output: Contribution to journalJournal articleResearchpeer-review

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    Abstract

    Coherent structures and mixing in the flow field of a jet in crossflow have been studied using computational (large eddy simulation) and experimental (particle image velocimetry and laser-induced fluorescence) techniques. The mean scalar fields and turbulence statistics as determined by both are compared for circular, elliptic, and square nozzles. For the latter configurations, effects of orientation are considered. The computations reveal that the distribution of a passive scalar in a cross-sectional plane can be single- or double-peaked, depending on the nozzle shape and orientation. A proper orthogonal decomposition of the transverse velocity indicates that coherent structures may be responsible for this phenomenon. Nozzles which have a single-peaked distribution have stronger modes in transverse direction. The global mixing performance is superior for these nozzle types. This is the case for the blunt square nozzle and for the elliptic nozzle with high aspect ratio. It is further demonstrated that the flow field contains large regions in which a passive scalar is transported up the mean gradient (counter-gradient transport) which implies failure of the gradient diffusion hypothesis.
    Original languageEnglish
    JournalFlow, Turbulence and Combustion
    Volume80
    Pages (from-to)255-283
    ISSN1386-6184
    DOIs
    Publication statusPublished - 2008

    Cite this

    Salewski, Mirko ; Stankovic, D. ; Fuchs, L. / Mixing in Circular and Non-circular Jets in Crossflow. In: Flow, Turbulence and Combustion. 2008 ; Vol. 80. pp. 255-283.
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    author = "Mirko Salewski and D. Stankovic and L. Fuchs",
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    Mixing in Circular and Non-circular Jets in Crossflow. / Salewski, Mirko; Stankovic, D.; Fuchs, L.

    In: Flow, Turbulence and Combustion, Vol. 80, 2008, p. 255-283.

    Research output: Contribution to journalJournal articleResearchpeer-review

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    T1 - Mixing in Circular and Non-circular Jets in Crossflow

    AU - Salewski, Mirko

    AU - Stankovic, D.

    AU - Fuchs, L.

    PY - 2008

    Y1 - 2008

    N2 - Coherent structures and mixing in the flow field of a jet in crossflow have been studied using computational (large eddy simulation) and experimental (particle image velocimetry and laser-induced fluorescence) techniques. The mean scalar fields and turbulence statistics as determined by both are compared for circular, elliptic, and square nozzles. For the latter configurations, effects of orientation are considered. The computations reveal that the distribution of a passive scalar in a cross-sectional plane can be single- or double-peaked, depending on the nozzle shape and orientation. A proper orthogonal decomposition of the transverse velocity indicates that coherent structures may be responsible for this phenomenon. Nozzles which have a single-peaked distribution have stronger modes in transverse direction. The global mixing performance is superior for these nozzle types. This is the case for the blunt square nozzle and for the elliptic nozzle with high aspect ratio. It is further demonstrated that the flow field contains large regions in which a passive scalar is transported up the mean gradient (counter-gradient transport) which implies failure of the gradient diffusion hypothesis.

    AB - Coherent structures and mixing in the flow field of a jet in crossflow have been studied using computational (large eddy simulation) and experimental (particle image velocimetry and laser-induced fluorescence) techniques. The mean scalar fields and turbulence statistics as determined by both are compared for circular, elliptic, and square nozzles. For the latter configurations, effects of orientation are considered. The computations reveal that the distribution of a passive scalar in a cross-sectional plane can be single- or double-peaked, depending on the nozzle shape and orientation. A proper orthogonal decomposition of the transverse velocity indicates that coherent structures may be responsible for this phenomenon. Nozzles which have a single-peaked distribution have stronger modes in transverse direction. The global mixing performance is superior for these nozzle types. This is the case for the blunt square nozzle and for the elliptic nozzle with high aspect ratio. It is further demonstrated that the flow field contains large regions in which a passive scalar is transported up the mean gradient (counter-gradient transport) which implies failure of the gradient diffusion hypothesis.

    U2 - 10.1007/s10494-007-9119-x

    DO - 10.1007/s10494-007-9119-x

    M3 - Journal article

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    SP - 255

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    JO - Flow, Turbulence and Combustion

    JF - Flow, Turbulence and Combustion

    SN - 1386-6184

    ER -