Avancerad sökning

Hittade 4 avhandlingar som matchar ovanstående sökkriterier.

  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. Turbomachinery Aeroacoustic Calculations using Nonlinear Methods

    Författare :Martin Olausson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Nonlinear; CFD; Time Spectral; CAA; Ffowcs-Williams Hawkings; Broadband; Time lag; Computational Aeroacoustics; Fan-Noise; Rotor-Stator interaction; Buffer layer; Oscillating sphere; Newton-GMRES; Computational Fluid Dynamics; Acoustic analogies; Sponge; Counter-Rotating Propfan; Harmonic Balance Technique; Tone; FWH; Chorochronic periodicity; Hybrid RANS LES;

    Sammanfattning : Noise regulations for aircraft that fly over populated areas are becoming continuously stricter. This in combination with increasing computational capabilities has boosted interest in aeroacoustic computations in the aerospace industry. LÄS MER

  4. 3. Pressure driven instabilities in the reversed-field pinch : numerical and theoretical studies

    Författare :Ahmed Akram Mirza; Jan Scheffel; Roberto Paccagnella; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Fusion plasma; thermonuclear; Reversed-field pinch; resistive MHD; resistive g modes; thermal conduction; the boundary value theory;

    Sammanfattning : According to classical linearized resistive magnetohydrodynamics theory, pressuredriven modes are unstable in the reversed-field pinch (RFP) due to unfavorable magnetic field line curvature. The result is based on the assumption of an adiabatic energy equation where anisotropic thermal conduction effects are ignored as compared to convection and compression. LÄS MER

  5. 4. Methods for Frequency Domain Estimation of Continuous-Time Models

    Författare :Jonas Gillberg; Lennart Ljung; Fredrik Gustafsson; Linköpings universitet; []
    Nyckelord :TECHNOLOGY; TEKNIKVETENSKAP;

    Sammanfattning : Approaching parameter estimation from the discrete-time domain is the dominating paradigm in system identification. Identification of continuous-time models on the other hand is motivated by the fact that modelling of physical systems often take place in continuous-time. LÄS MER