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Browsing by Subject "turbulence"

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  • thumbnail.journal.alt
    Item type:Article, Access status: Open Access ,
    Parabolic turbulence k-epsilon model with applications in fluid flows through permeable media
    (Wydawnictwa AGH, 2024) Oliveira, Hermenegildo Borges de
    In this work, we study a one-equation turbulence $k$-epsilon model that governs fluid flows through permeable media. The model problem under consideration here is derived from the incompressible Navier-Stokes equations by the application of a time-averaging operator used in the $k$-epsilon modeling and a volume-averaging operator that is characteristic of modeling unsteady porous media flows. For the associated initial- and boundary-value problem, we prove the existence of suitable weak solutions (average velocity field and turbulent kinetic energy) in the space dimensions of physics interest.
  • thumbnail.journal.alt
    Item type:Article, Access status: Open Access ,
    Thermoanemometrical study of flow structure through a centrifugal fan
    (2013) Fortuna, Stanisław; Górski, Jan; Siwek, Tomasz
    Recognition of the spatial kinematics of the flow domain and its relation to the fan impeller geometry has a key influence on the machine design and better performance parameters. In this work some experimental results are presented of the measurements of the absolute velocity, its components and turbulence of the air flow through the radial fan rotor operating in various configurations. As the main measuring tool a three-axial hot-wire anemometer (CTA) probe has been used. The anemometer cooperates with a specialized software prepared by the authors for the spatial analysis of the flow field considered. In particular, the distribution of the circumferential velocity components behind the impeller rim has been examined, which affects directly the fan efficiency. As a result of the flow analysis behind the rotor rim a relationship has been established between the degree of turbulence and the machine efficiency. On the basis of the changes in the averaged-in-time velocity field behind the rim, the outflow of air from the blade passage has been evaluated.