Sökning: "linear cascade"

Visar resultat 1 - 5 av 39 avhandlingar innehållade orden linear cascade.

  1. 1. Modeling of Unsteady Flow Effects in Throughflow Calculations

    Författare :Magnus Stridh; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; rotor-stator interaction; mixing-plane; linear Navier-Stokes; cascade; turbomachinery; transport equation; Linear harmonic; compressor; throughflow; turbine; Deterministic stress terms;

    Sammanfattning : In this work an evaluation of a deterministic stress transport model and a linearized Navier-Stokes harmonic approach for including unsteady effects in the steady mixing-plane computations of a multistage transonic compressor has been performed. The results of these two models are compared with those of time-average time-accurate solutions. LÄS MER

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

    Författare :Magnus Stridh; Chalmers tekniska högskola; []
    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

  4. 3. Dynamic properties of two-dimensional and quasi-geostrophic turbulence

    Författare :Andreas Vallgren; Erik Lindborg; Guido Boffetta; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; two-dimensional turbulence; decaying turbulence; quasi-geostrophic turbulence; direct numerical simulation DNS ; coherent vortices; energy cascade; enstrophy cascade; intermittency; massively parallel simulations; locality iii; Non-linear dynamics; chaos; Icke-linjär dynamik; kaos;

    Sammanfattning : Two codes have been developed and implemented for use on massively parallelsuper computers to simulate two-dimensional and quasi-geostrophic turbulence.The codes have been found to scale well with increasing resolution and width ofthe simulations. LÄS MER

  5. 4. Quantitative Modeling of Gain in Quantum Cascade Lasers under Operational Intensities

    Författare :David Winge; Matematisk fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; non-linear response; quantum cascade lasers; modelling; Non-equilibrium Green s functions; Gain clamping; Fysicumarkivet A:2016:Winge; kvantkaskadlaser; terahertz; infrarött; Halvledarfysik; spektroskopi; simulering;

    Sammanfattning : This thesis adresses modeling of quantum cascade lasers using non-equilibrium Green’s functions. Focus lies on the quantitative modeling of the gain when the systems are exposed to strong laser fields, as under realistic opertional conditions. LÄS MER

  7. 5. Turbine Outlet Guide Vane Flows

    Författare :Johan Hjärne; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Spalart-Allmaras model; k-ω SST model; linear cascade; secondary flows; turbine exhaust casing; RSM; k-ε realizable model; turbine rear frame; engine mount bump; tail bearing housing; Outlet guide vane;

    Sammanfattning : New design goals on modern jet engines often leads to more highly loaded turbines with fewer stages in order to save weight and cost. This gives higher swirl angles into the outlet guide vane (OGV), implying a more difficult aerodynamic design. LÄS MER