Articles producció científica> Enginyeria Química

Wake behind a discontinuous cylinder: unveiling the role of the large scales in wake growth and entrainment

  • Dades identificatives

    Identificador: imarina:9245508
    Autors:
    Mandava, V. S. R.Herrero, JoanKopp, Gregory A.Giralt, Francesc
    Resum:
    The turbulent flow in the wake of a discontinuous cylinder (DC) was investigated. The DC geometry consisted of cylinder segments 5D long (with D being the diameter of the cylinder) separated by gaps of width 2.5D. Particle image velocimetry and hot-wire anemometry were used to analyse the flow at two Reynolds numbers, Re = 4000 and 10000, for x/D <= 180. Large eddy simulations for both the DC and the infinite continuous cylinder (CC) wakes were also carried out at Re = 10000. The DC configuration was devised to trigger the shedding of horseshoe vortices (HSV) in the very-near-wake region with the intent of illustrating the role that these three-dimensional HSVs, previously identified in the far-wake region of CC, play in the entrainment process in turbulent wakes. The DC geometry produced HSVs by the interaction between the high momentum flow through the gaps and the main spanwise vortex shed behind each cylinder segment, while in the CC wake they evolve from near-wake instabilities straddled with hairpin vortices that detach spanwise vorticity from the shed Karman vortices. The DC wake was found to grow and spread in the transverse direction with a much faster rate than for the CC wake, up until approximately x/D approximate to 50. Prior to this location, the enhanced growth rate caused by the shear-aligned HSV led to a wake width of approximately 3 times that of the CC wake, with a maximum mean velocity deficit that was approximately half.
  • Altres:

    Autor segons l'article: Mandava, V. S. R.; Herrero, Joan; Kopp, Gregory A.; Giralt, Francesc;
    Departament: Enginyeria Química
    Autor/s de la URV: Giralt Prat, Francesc d'Assís / Herrero Sabartés, Juan
    Paraules clau: Wall proximity Wakes Vortex shedding Velocity-field Turbulent/non-turbulent interface Turbulent convection Transport Transition Temperature Simulation Large eddies Flow Circular-cylinder
    Resum: The turbulent flow in the wake of a discontinuous cylinder (DC) was investigated. The DC geometry consisted of cylinder segments 5D long (with D being the diameter of the cylinder) separated by gaps of width 2.5D. Particle image velocimetry and hot-wire anemometry were used to analyse the flow at two Reynolds numbers, Re = 4000 and 10000, for x/D <= 180. Large eddy simulations for both the DC and the infinite continuous cylinder (CC) wakes were also carried out at Re = 10000. The DC configuration was devised to trigger the shedding of horseshoe vortices (HSV) in the very-near-wake region with the intent of illustrating the role that these three-dimensional HSVs, previously identified in the far-wake region of CC, play in the entrainment process in turbulent wakes. The DC geometry produced HSVs by the interaction between the high momentum flow through the gaps and the main spanwise vortex shed behind each cylinder segment, while in the CC wake they evolve from near-wake instabilities straddled with hairpin vortices that detach spanwise vorticity from the shed Karman vortices. The DC wake was found to grow and spread in the transverse direction with a much faster rate than for the CC wake, up until approximately x/D approximate to 50. Prior to this location, the enhanced growth rate caused by the shear-aligned HSV led to a wake width of approximately 3 times that of the CC wake, with a maximum mean velocity deficit that was approximately half.
    Àrees temàtiques: Physics, fluids & plasmas Mechanics of materials Mechanics Mechanical engineering Matemática / probabilidade e estatística Interdisciplinar Geociências Engenharias iv Engenharias iii Engenharias ii Engenharias i Condensed matter physics Astronomia / física Applied mathematics
    Accès a la llicència d'ús: https://creativecommons.org/licenses/by/3.0/es/
    Adreça de correu electrònic de l'autor: fgiralt@urv.cat joan.herrero@urv.cat
    Identificador de l'autor: 0000-0001-8501-1187
    Data d'alta del registre: 2024-09-21
    Versió de l'article dipositat: info:eu-repo/semantics/acceptedVersion
    Enllaç font original: https://www.cambridge.org/core/journals/journal-of-fluid-mechanics/article/abs/wake-behind-a-discontinuous-cylinder-unveiling-the-role-of-the-large-scales-in-wake-growth-and-entrainment/A0FBA63E79B8CF37FE401F03049785CA#
    URL Document de llicència: https://repositori.urv.cat/ca/proteccio-de-dades/
    Referència a l'article segons font original: Journal Of Fluid Mechanics. 936
    Referència de l'ítem segons les normes APA: Mandava, V. S. R.; Herrero, Joan; Kopp, Gregory A.; Giralt, Francesc; (2022). Wake behind a discontinuous cylinder: unveiling the role of the large scales in wake growth and entrainment. Journal Of Fluid Mechanics, 936(), -. DOI: 10.1017/jfm.2022.32
    DOI de l'article: 10.1017/jfm.2022.32
    Entitat: Universitat Rovira i Virgili
    Any de publicació de la revista: 2022
    Tipus de publicació: Journal Publications
  • Paraules clau:

    Applied Mathematics,Condensed Matter Physics,Mechanical Engineering,Mechanics,Mechanics of Materials,Physics, Fluids & Plasmas
    Wall proximity
    Wakes
    Vortex shedding
    Velocity-field
    Turbulent/non-turbulent interface
    Turbulent convection
    Transport
    Transition
    Temperature
    Simulation
    Large eddies
    Flow
    Circular-cylinder
    Physics, fluids & plasmas
    Mechanics of materials
    Mechanics
    Mechanical engineering
    Matemática / probabilidade e estatística
    Interdisciplinar
    Geociências
    Engenharias iv
    Engenharias iii
    Engenharias ii
    Engenharias i
    Condensed matter physics
    Astronomia / física
    Applied mathematics
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