Sökning: "wall turbulence"

Visar resultat 21 - 25 av 179 avhandlingar innehållade orden wall turbulence.

  1. 21. Turbulence modeling using automated code generation applied to asymmetric diffuser flow

    Författare :Johan Gullman-Strand; KTH; []
    Nyckelord :Fluid mechanics; Turbulence modeling; Explicit algebraic Reynolds stress model; Low-Re K-w; Automated code generation; Wall distance function;

    Sammanfattning : .... LÄS MER

  3. 22. Large Eddy Simulation of Turbulent Flows in Combustor Related Geometries

    Författare :Jessica Gullbrand; Institutionen för energivetenskaper; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Mechanical engineering; Energiforskning; Energy research; Cartesian grid; high order wall treatment; SGS models; turbulence; subgrid scale models; LES; Large Eddy Simulation; akustik; vibrationer; vakuumteknik; hydraulik; vibration and acoustic engineering; Maskinteknik; vacuum technology; hydraulics;

    Sammanfattning : Numerical simulations using Large Eddy Simulation (LES) are applied to turbulent swirling flow fields. The swirling motion is often introduced into combustors to act as flame holders or enhance the mixing between species. Different turbulence models capture the swirling motion more or less accurately. LÄS MER

  4. 23. Transition to turbulence in the asymptotic suction boundary layer

    Författare :Taras Khapko; Dan Henningson; Philipp Schlatter; Yohann Duguet; Marc Avila; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; boundary layers; instability; laminar-turbulent transition; dynamical systems; edge states; near-wall turbulence; laminarisation;

    Sammanfattning : The focus of this thesis is on the numerical study of subcritical transition to turbulence in the asymptotic suction boundary layer (ASBL). Applying constant homogeneous suction prevents the spatial growth of the boundary layer, granting access to the asymptotic dynamics. LÄS MER

  5. 24. Numerical studies of transtion in wall-bounded flows

    Författare :Ori Levin; Dan Henningson; Nikolaus Adams; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; boundary layer; suction; wall jet; streaks; waves; periodic disturbance; localized disturbance; turbulent spot; algebraic growth; exponential growth; stability; transition thresholds; transition prediction; PSE; DNS; Fluid mechanics; Strömningsmekanik;

    Sammanfattning : Disturbances introduced in wall-bounded flows can grow and lead to transition from laminar to turbulent flow. In order to reduce losses or enhance mixing in energy systems, a fundamental understanding of the flow stability and transition mechanism is important. LÄS MER

  7. 25. Experimental study on turbulent boundary-layer flows with wall transpiration

    Författare :Marco Ferro; Jens Fransson; Bengt Fallenius; Joseph Klewicki; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Turbulent boundary layer; boundary-layer suction; boundary-layer blowing; wall-bounded turbulent flows; self-sustained turbulence; Engineering Mechanics; Teknisk mekanik;

    Sammanfattning : Wall transpiration, in the form of wall-normal suction or blowing through a permeable wall, is a relatively simple and effective technique to control the behaviour of a boundary layer. For its potential applications for laminar-turbulent transition and separation delay (suction) or for turbulent drag reduction and thermal protection (blowing), wall transpiration has over the past decades been the topic of a significant amount of studies. LÄS MER