Sökning: "computational fluid dynamic simulation"

Visar resultat 11 - 15 av 43 avhandlingar innehållade orden computational fluid dynamic simulation.

  1. 11. 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

  3. 12. 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

  4. 13. High Performance Adaptive Finite Element Methods : With Applications in Aerodynamics

    Författare :Niclas Jansson; Johan Hoffman; Johan Jansson; Vincent Heuveline; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : The massive computational cost for resolving all scales in a turbulent flow makes a direct numerical simulation of the underlying Navier-Stokes equations impossible in most engineering applications. Recent advances in adaptive finite element methods offer a new powerful tool in Computational Fluid Dynamics (CFD). LÄS MER

  5. 14. Accuracy, efficiency and robustness for rigid particle simulations in Stokes flow

    Författare :Anna Broms; Anna-Karin Tornberg; Mattias Sandberg; Eric Keaveny; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Stokes flow; rigid particles; accuracy; fundamental solutions; method of images; multiblob; contact avoiding; complementarity problem; barrier method; elliptic PDE; grid optimisation; pair-correction; boundary integral equations; Stokesflöde; noggrannhet; stela partiklar; fundamentallösningar; randintegralekvation; reflektionspunkter; multiblob; kontaktundvikande algoritmer; komplementaritetsproblem; barriärmetod; elliptisk PDE; gridoptimering; parkorrektion; Numerical Analysis; Numerisk analys;

    Sammanfattning : The thesis concerns simulation techniques for systems of nano- to micro-scaled rigid particles immersed in a viscous fluid, ubiquitous in nature and industry. With negligible fluid inertia, the set of PDEs known as the Stokes equations can be used to model the hydrodynamics. LÄS MER

  7. 15. Effects of boundary conditions and unsteadiness on draft tube flow

    Författare :Michel Cervantes; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Strömningslära; Fluid Mechanics;

    Sammanfattning : The present research focuses on flow properties of the elbow draft tube. This element has a major function in low head turbines, since up to half of the losses may arise there at part load. The use of computational fluid dynamic (CFD) to redisign a draft tube necessitates detailed knowledged of the boundary conditions. LÄS MER