Sökning: "Wall-Bounded Turbulent Flows"

Visar resultat 11 - 15 av 32 avhandlingar innehållade orden Wall-Bounded Turbulent Flows.

  1. 11. Modelling Techniques for Large-Eddy Simulation of Wall-Bounded Turbulent Flows

    Författare :Timofey Mukha; Mattias Liefvendahl; Hrvoje Jasak; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Wall modelling; Inflow generation; Large-eddy simulation; OpenFOAM; Computational fluid dynamics; Scientific Computing; Beräkningsvetenskap;

    Sammanfattning : Large-eddy simulation (LES) is a highly accurate turbulence modelling approach in which a wide range of spatial and temporal scales of the flow are resolved. However, LES becomes prohibitively computationally expensive when applied to wall-bounded flows at high Reynolds numbers, which are typical of many industrial applications. LÄS MER

  3. 12. Hot wire and PIV studies of transonic turbulent wall-bounded flows

    Författare :Timmy Sigfrids; KTH; []
    Nyckelord :fluid mechanics; compressible flow; turbulence; boundary layer; hot-wire anemometry; PIV; shock wave boundary layer interaction; shape factor;

    Sammanfattning : The compressible turbulent boundary layer developing over atwo-dimensional bump which leads to a supersonic pocket with aterminating shock wave has been studied. The measurements havebeen made with hot-wire anemometry and Particle ImageVelocimetry (PIV). LÄS MER

  4. 13. Turbulent flows over permissive boundaries and porous walls

    Författare :Seyed Morteza Habibi Khorasani; Shervin Bagheri; Geert Brethouwer; Alfredo Soldati; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Direct numerical simulations; wall-bounded turbulence; flow control; porous walls; heat transfer; Direkta numeriska simuleringar; väggbunden turbulens; flödeskontroll; porösa väggar; värmeöverföring; Teknisk mekanik; Engineering Mechanics;

    Sammanfattning : This thesis investigates how in wall-bounded turbulent flows changes to the wall can induce changes in the flow. To this end, we investigate the use of wall boundary conditions meant to mimic the effect of textured surfaces. LÄS MER

  5. 14. Spectral-element simulations of turbulent wall-bounded flows including transition and separation

    Författare :Johan Malm; Dan Henningson; Philipp Schlatter; Suad Jakirlic; KTH; []
    Nyckelord :spectral-element method; direct numerical simulation DNS ; large-eddy simulation LES ; turbulence; transition; over-integration; three-dimensional separation; massively parallel simulations; proper orthogonal decomposition POD ; Koopman modes; vorticity stretching; coherence; SRA - E-vetenskap SeRC ; SRA - E-Science SeRC ;

    Sammanfattning : The spectral-element method (SEM) is used to study wall-bounded turbulent flowsin moderately complex geometries. The first part of the thesis is devoted to simulations of canonical flow cases, such as temporal K-type transitionand turbulent channel flow, to investigate general resolution requirements and computational efficiency of the numerical code nek5000. LÄS MER

  7. 15. Modelling and control of turbulent and transitional flows

    Författare :Pierluigi Morra; Dan S. Henningson; Ardeshir Hanifi; André V. G. Cavalieri; Shervin Bagheri; Aimee S. Morgans; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; reduced order modeling; flow control; resolvent analysis; transi- tional boundary layer; turbulent boundary layer; drag reduction; high-fidelity wall-turbulence modelling; modellreduktion; strömningskontroll; resolvent analys; laminär- turbulent omslag; turbulent gränsskikt; motståndsminskning; väggturbulens modellering; Engineering Mechanics; Teknisk mekanik;

    Sammanfattning : The dynamics of fluid motion can accurately be described by the Navier– Stokes equations. Manipulating these equations to reduce their complexity but preserving their main characteristics has always been a key research activity in the field of fluid mechanics. LÄS MER