Search for dissertations about: "Vorticity"

Showing result 1 - 5 of 45 swedish dissertations containing the word Vorticity.

  2. 1. On Steady Water Waves and Their Properties

    Author : Mats Ehrnström; Matematik (naturvetenskapliga fakulteten); []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Particle trajectories; Water waves; Vorticity; Maximum principles; Elliptic equations;

    Abstract : Abstract: This thesis consists of four papers related to various aspects of steady water waves. Paper I: Deep-water waves with vorticity: symmetry and rotational behaviour. We show that for steady, periodic, and rotational gravity deep-water waves, a monotone surface profile between troughs and crests implies symmetry. READ MORE

  4. 2. Studies of sound generation and propagation in flow ducts

    Author : Fabrice Ducret; Mats Åbom; Andy Moorhouse; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; two-port; plane wave; HVAC system; tailpipe; exhaust system; flexible duct; pipe; reflection coefficient; impedance; flow noise; vorticity; damping; scaling laws; impedance; transmission loss; perforated plate; slit; non linearity; Acoustics; Akustik;

    Abstract : This thesis contains three papers investigating problems of interest for noise control in ducts. The first part of this thesis treats the sound propagation in rectangular ducts with flexible walls. Various experimental techniques are performed to measure the internal sound propagation and radiation to the surrounding. READ MORE

  5. 3. Small-amplitude steady water waves with vorticity

    Author : Evgeniy Lokharu; Vladimir Kozlov; Johan Thim; Tomas Sjödin; Mark Groves; Linköpings universitet; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Abstract : The problem of describing two-dimensional traveling water waves is considered. The water region is of finite depth and the interface between the region and the air is given by the graph of a function. We assume the flow to be incompressible and neglect the effects of surface tension. READ MORE

  6. 4. On stability of vortices and vorticity generated by actuator lines

    Author : Vitor Gabriel Kleine; Dan S. Henningson; Ardeshir Hanifi; Stéphane Le Dizès; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Teknisk mekanik; Engineering Mechanics;

    Abstract : Vortices are present in nature and in many flows of industrial importance. The stability of configurations of vortices can have real-world consequences, because vortices play a crucial role in accelerated mixing. In particular, vortices are present in the wake of wind turbines and other rotors. READ MORE

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

    Author : Johan Malm; Dan Henningson; Philipp Schlatter; Suad Jakirlic; KTH; []
    Keywords : 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 ;

    Abstract : 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. READ MORE