Sökning: "subgrid-scale"

Visar resultat 1 - 5 av 19 avhandlingar innehållade ordet subgrid-scale.

  1. 1. Subgrid-scale modelling for large-eddy simulation including scalar mixing in rotating turbulent shear flows

    Författare :Linus Marstorp; Arne Johansson; Lars-Erik Eriksson; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Turbulence; large-eddy simulation; subgrid-scale model; Fluid mechanics; Strömningsmekanik;

    Sammanfattning : The aim of the present study is to develop subgrid-scale models that are relevant for complex flows and combustion. A stochastic model based on a stochastic Smagorinsky constant with adjustable variance and time scale is proposed. LÄS MER

  3. 2. Modelling of subgrid-scale stress and passive scalar flux in large eddy simulations of wall bounded turbulent flows

    Författare :Linus Marstorp; Arne V. Johansson; Pierre Comte; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Turbulence; large-eddy simulation; subgrid-scale model; Fluid mechanics; Strömningsmekanik;

    Sammanfattning : The aim of the thesis is to develop and validate subgrid-scale models that are relevant for large eddy simulations of complex flows including scalar mixing. A stochastic Smagorinsky model with adjustable variance and time scale is developed by adding a stochastic component to the Smagorinsky constant. LÄS MER

  4. 3. Explicit algebraic subgrid-scale stress and passive scalar flux modeling in large eddy simulation

    Författare :Amin Rasam; Arne V. Johansson; Shia-Hui Peng; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Turbulence; Large eddy simulation; explicit algebraic subgrid-scale model; passive scalar; stochastic modeling; backscatter; Fluid mechanics; Strömningsmekanik;

    Sammanfattning : The present thesis deals with a number of challenges in the field of large eddy simulation (LES). These include the performance of subgrid-scale (SGS) models at fairly high Reynolds numbers and coarse resolutions, passive scalar and stochastic modeling in LES. LÄS MER

  5. 4. Large Eddy Simulations of Separated Compressible Flows around Wing Sections

    Författare :Jörgen Held; Strömningsteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; turbulence; subgrid-scale; shock-boundary layer interaction; wing section; transonic; subsonic; compressible; separated; Large eddy simulation; LES; PVM; Mechanical engineering; hydraulics; vacuum technology; vibration and acoustic engineering; Maskinteknik; hydraulik; vakuumteknik; vibrationer; akustik;

    Sammanfattning : This thesis concerns numerical calculations of compressible separated flows, with and without shocks, around wing sections using Large Eddy Simulations (LES). The considered geometries are the NACA 0012 wing section and the ONERA AT15A wing section. LÄS MER

  7. 5. Anisotropy-resolving subgrid-scale modelling using explicit algebraic closures for large eddy simulation

    Författare :Amin Rasam; Arne Johansson; Bernard Geurts; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Turbulence; large eddy simulation; explicit algebraic subgridscale model; passive scalar; stochastic modelling; periodic hill flow; Engineering Mechanics; Teknisk mekanik;

    Sammanfattning : The present thesis deals with the development and performance analysis ofanisotropy-resolving models for the small, unresolved scales (”sub-grid scales”,SGS) in large eddy simulation (LES). The models are characterised by a descriptionof anisotropy by use of explicit algebraic models for both the subgridscale(SGS) stress tensor (EASSM) and SGS scalar flux vector (EASSFM). LÄS MER