Sökning: "Susann Boij"

Visar resultat 1 - 5 av 12 avhandlingar innehållade orden Susann Boij.

  1. 1. Acoustic scattering in ducts and influence of flow coupling

    Författare :Susann Boij; KTH; []
    Nyckelord :sound; vortex sheet; flow separation; end correction; Strouhal number; non-orthogonal modes; energy balance; TECHNOLOGY; TEKNIKVETENSKAP;

    Sammanfattning : The subject of this thesis is the acoustic properties offlow duct area expansions and the influence of flow-acousticcoupling at sharp edges. For low Mach number flow, significantinteraction between the sound field and the flow field canoccur at such points of flow separation. LÄS MER

  2. 2. Absorption of Sound : On the effects of field interaction on absorber performance

    Författare :Anna Färm; Mats Åbom; Ragnar Glav; Susann Boij; Gareth Bennett; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Sound absorption; Porous absorbers; Bulk reaction; Local reaction; Boundary layer; Grazing flow; Temperature gradients; Surface impedance; Sound field; Pass-by noise; Farkostteknik; Vehicle and Maritime Engineering;

    Sammanfattning : Environmental noise has for decades been a well known problem, especially in urban areas. As noise requirements for vehicles are sharpened, noise reducing concepts are needed in early design stages requiring accurate simulations to support the design. LÄS MER

  3. 3. Aeroacoustic Characterization using Multiport Methods

    Författare :Andreas Holmberg; Hans Bodén; Mats Åbom; Susann Boij; Lars Enghardt; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Aeroacoustics; Multiport; Experiments; Computational Aeroacoustics; Mixer Plate; T-junction.;

    Sammanfattning : Noise is a major environmental pollutant, which can inict physical and psychologicalinjury. An important noise contribution stems from aeroacousticsources, which are found in e.g., ventilation ducts, engine exhaust systems andairplane engines. LÄS MER

  4. 4. A Linearized Navier-Stokes Equations Methodology for Aeroacoustic and Thermoacoustic Simulations

    Författare :Wei Na; Susann Boij; Gunilla Efraimsson; Niklas Andersson; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; Linearized Navier-Stokes Equations LNSE ; frequency domain; tube row heat exchanger; hybrid liner; thermoacoustic instabilities; entropy waves; Rijke-tube; nozzle; Teknisk mekanik; Engineering Mechanics;

    Sammanfattning : Aeroengine noise is one of the dominating noise sources in today’s aircraft. Reduction of the aeroengine noise is related to multiphysics phenomena, and that is subject to different mechanisms, e.g., the coupling between turbulence, flame and sound waves. LÄS MER

  5. 5. Frequency Domain Linearized Navier-Stokes Equations Methodology for Aero-Acoustic and Thermoacoustic Simulations

    Författare :Wei Na; Gunilla Efraimsson; Susann Boij; Martinez Lera Paula; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; Linearized Navier-Stokes Equations; frequency domain; fluid equivalent model; hybrid liner; thermoacoustic instabilities; Rijke-tube; Teknisk mekanik; Engineering Mechanics;

    Sammanfattning : The first part of the thesis focuses on developing a numerical methodology to simulate the acoustic properties of a hybrid liner consisting of a perforated plate, a porous layer and a Helmholtz cavity. Liners are always a standard way to reduce noise in today’s aeroengines, e.g. LÄS MER