Sökning: "spectral turbulence"

Visar resultat 1 - 5 av 46 avhandlingar innehållade orden spectral turbulence.

  1. 1. Time Spectral Methods - Towards Plasma Turbulence Modelling

    Författare :Kristoffer Lindvall; Jan Scheffel; Carl Sovinec; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Fusion; Turbulence; Micro-instabilities; Time-spectral; Navier-Stokes; MHD; Weiland model; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : Energy comes in two forms; potential energy and kinetic energy. Energyis stored as potential energy and released in the form of kinetic energy. This process of storage and release is the basic strategy of all energy alternatives in use today. This applies to solar, wind, fossil fuels, and the list goes on. LÄS MER

  3. 2. Statistical characteristics of two-dimensional and quasigeostrophic turbulence

    Författare :Andreas Vallgren; Erik Lindborg; Johan Nilsson; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; two-dimensional turbulence; decaying turbulence; quasigeostrophic turbulence; direct numerical simulation DNS ; coherent vortices; energy cas- cade; enstrophy cascade; intermittency; massively parallel simulations; 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 quasigeostrophic turbulence.The codes have been found to scale well with increasing resolution and width ofthe simulations. LÄS MER

  4. 3. Spectral-element simulations of separated turbulent internal flows

    Författare :Johan Ohlsson; Dan Prof Henningson; Jesper Oppelstrup; KTH; []
    Nyckelord :spectral element method; direct numerical simulations DNS ; turbulence; dealiasing; three-dimensional separation; massively parallel simulations;

    Sammanfattning : .... LÄS MER

  5. 4. 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. 5. 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