Sökning: "unsteady"

Visar resultat 1 - 5 av 138 avhandlingar innehållade ordet unsteady.

  1. 1. Modeling Unsteady flow Effects in 3D Throughflow Calculations

    Författare :Magnus Stridh; [2006]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; throughflow; turbomachinery; mixing-plane; rotor-stator interaction; cascade; Deterministic stress terms; Linear harmonic; compressor; preconditioned GMRES; Unsteady; linear Navier-Stokes; turbine;

    Sammanfattning : The flow field in a transonic multistage compressor is compressible, three-dimensional and highly unsteady and can be predicted in principle by the exact time-accurate Navier-Stokes equations. The high Reynolds number encountered in multistage turbomachinery together with the wall-bounded nature of the flow environment however prevent the use of DNS to solve the exact N-S equations. LÄS MER

  2. 2. Numerical Investigation of Unsteady Crosswind Aerodynamics for Ground Vehicles

    Detta är en avhandling från Stockholm : KTH

    Författare :Tristan Favre; KTH.; [2009]
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Aerodynamics; Vehicle Aerodynamics; Unsteady Aerodynamics; Crosswind; Unsteady Crosswind Aerodynamics; Detached-Eddy Simulations; DES; TECHNOLOGY Engineering mechanics Vehicle engineering; TEKNIKVETENSKAP Teknisk mekanik Farkostteknik; TECHNOLOGY Engineering mechanics Fluid mechanics; TEKNIKVETENSKAP Teknisk mekanik Strömningsmekanik;

    Sammanfattning : Ground vehicles are subjected to crosswind from various origins such as weather, topography of the ambient environment (land, forest, tunnels, high bushes...) or surrounding traffic. LÄS MER

  3. 3. Realistic simulations of delta wing aerodynamics using novel CFD methods

    Detta är en avhandling från Stockholm : KTH

    Författare :Stefan Görtz; KTH.; [2005]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Space and plasma physics; CFD; aerodynamics; flow physics; steady; unsteady; delta wing; vortical flow; Rymd- och plasmafysik; NATURAL SCIENCES Physics Geocosmophysics and plasma physics Space physics; NATURVETENSKAP Fysik Geokosmofysik och plasmafysik Rymdfysik;

    Sammanfattning : The overall goal of the research presented in this thesis is to extend the physical understanding of the unsteady external aerodynamics associated with highly maneuverable delta-wing aircraft by using and developing novel, more efficient computational fluid dynamics (CFD) tools. More specific, the main purpose is to simulate and better understand the basic fluid phenomena, such as vortex breakdown, that limit the performance of delta-wing aircraft. LÄS MER

  4. 4. Accurate physical and numerical modeling of complex vortex phenomena over delta wings

    Detta är en avhandling från Stockholm : KTH

    Författare :Simone Crippa; KTH.; [2006]
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; computational fluid dynamics; CFD; vortical flow; delta wing; aerodynamics; flow physics; steady; unsteady; TECHNOLOGY Engineering mechanics Vehicle engineering; TEKNIKVETENSKAP Teknisk mekanik Farkostteknik;

    Sammanfattning : With this contribution to the AVT-113/VFE-2 task group it was possible to prove the feasibility of high Reynolds number CFD computations to resolve and thus better understand the peculiar dual vortex system encountered on the VFE-2 blunt leading edge delta wing. Initial investigations into this phenomenon seemed to undermine the hypothesis, that the formation of the inner vortex system relies on the laminar state of the boundary layer at separation onset. LÄS MER

  5. 5. Numerical computations of the unsteady flow in turbochargers

    Detta är en avhandling från Stockholm : KTH

    Författare :Fredrik Hellström; KTH.; [2010]
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Turbochargers; turbine; compressor; unsteady pulsatile flow; perturbations; Large Eddy Simulation; TECHNOLOGY Engineering mechanics Fluid mechanics; TEKNIKVETENSKAP Teknisk mekanik Strömningsmekanik;

    Sammanfattning : Turbocharging the internal combustion (IC) engine is a common technique to increase the power density. If turbocharging is used with the downsizing technique, the fuel consumption and pollution of green house gases can be decreased. LÄS MER