Articles producció científica> Enginyeria Mecànica

Direct numerical simulation of the fully developed turbulent free convection flow in an asymmetrically heated vertical channel

  • Identification data

    Identifier: imarina:9295696
    Authors:
    Pallares, JFabregat, ALei, CW
    Abstract:
    We report direct numerical simulations of the fully developed turbulent natural convection flow of a Boussinesq fluid (Pr = 0.71) in a vertical channel. One wall is heated with a constant heat flux and the other is assumed to be perfectly insulated. Simulations were performed at three different Rayleigh numbers (Ra = 5 × 105, 106 and 5 × 106). Predictions of the time averaged velocities, temperatures and intensities of the fluctuations agree with experiments reported in the literature. Under the fully developed flow conditions considered in this study the shear stress is greater on thermally active wall than that on the adiabatic wall, but the turbulent intensities and the turbulent shear stress are greater near the insulated wall. Conversely, the intensities of the temperature fluctuations and turbulent heat fluxes are higher near the thermally active wall than those near the adiabatic wall. Contrary to the vertical channel with constant but different wall temperatures, where buoyancy and turbulent shear dominate the generation of turbulent kinetic energy, in the asymmetrically heated channel the turbulent shear stress is the principal mechanism of turbulent kinetic energy production as in a forced convection channel flow.
  • Others:

    Author, as appears in the article.: Pallares, J; Fabregat, A; Lei, CW
    Department: Enginyeria Mecànica
    URV's Author/s: Fabregat Tomàs, Alexandre / Pallarés Curto, Jorge María
    Keywords: Vertical channel Turbulent flow Natural convection Laminar free-convection Direct numerical simulation Asymmetrical heating wall vertical channel solar chimney plates natural-convection natural convection infinite direct numerical simulation asymmetrical heating
    Abstract: We report direct numerical simulations of the fully developed turbulent natural convection flow of a Boussinesq fluid (Pr = 0.71) in a vertical channel. One wall is heated with a constant heat flux and the other is assumed to be perfectly insulated. Simulations were performed at three different Rayleigh numbers (Ra = 5 × 105, 106 and 5 × 106). Predictions of the time averaged velocities, temperatures and intensities of the fluctuations agree with experiments reported in the literature. Under the fully developed flow conditions considered in this study the shear stress is greater on thermally active wall than that on the adiabatic wall, but the turbulent intensities and the turbulent shear stress are greater near the insulated wall. Conversely, the intensities of the temperature fluctuations and turbulent heat fluxes are higher near the thermally active wall than those near the adiabatic wall. Contrary to the vertical channel with constant but different wall temperatures, where buoyancy and turbulent shear dominate the generation of turbulent kinetic energy, in the asymmetrically heated channel the turbulent shear stress is the principal mechanism of turbulent kinetic energy production as in a forced convection channel flow.
    Thematic Areas: Thermodynamics Matemática / probabilidade e estatística Interdisciplinar General engineering Engineering, mechanical Engineering (miscellaneous) Engineering (all) Engenharias iii Engenharias ii Engenharias i Condensed matter physics Ciências ambientais Astronomia / física Arquitetura e urbanismo
    licence for use: https://creativecommons.org/licenses/by/3.0/es/
    Author's mail: alexandre.fabregat@urv.cat jordi.pallares@urv.cat
    Author identifier: 0000-0002-6032-2605 0000-0003-0305-2714
    Record's date: 2024-08-03
    Papper version: info:eu-repo/semantics/publishedVersion
    Link to the original source: https://www.sciencedirect.com/science/article/pii/S1290072923002132
    Licence document URL: https://repositori.urv.cat/ca/proteccio-de-dades/
    Papper original source: International Journal Of Thermal Sciences. 191
    APA: Pallares, J; Fabregat, A; Lei, CW (2023). Direct numerical simulation of the fully developed turbulent free convection flow in an asymmetrically heated vertical channel. International Journal Of Thermal Sciences, 191(), -. DOI: 10.1016/j.ijthermalsci.2023.108352
    Article's DOI: 10.1016/j.ijthermalsci.2023.108352
    Entity: Universitat Rovira i Virgili
    Journal publication year: 2023
    Publication Type: Journal Publications
  • Keywords:

    Condensed Matter Physics,Engineering (Miscellaneous),Engineering, Mechanical,Thermodynamics
    Vertical channel
    Turbulent flow
    Natural convection
    Laminar free-convection
    Direct numerical simulation
    Asymmetrical heating
    wall
    vertical channel
    solar chimney
    plates
    natural-convection
    natural convection
    infinite
    direct numerical simulation
    asymmetrical heating
    Thermodynamics
    Matemática / probabilidade e estatística
    Interdisciplinar
    General engineering
    Engineering, mechanical
    Engineering (miscellaneous)
    Engineering (all)
    Engenharias iii
    Engenharias ii
    Engenharias i
    Condensed matter physics
    Ciências ambientais
    Astronomia / física
    Arquitetura e urbanismo
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