Sökning: "acoustic analysis"

Visar resultat 6 - 10 av 234 avhandlingar innehållade orden acoustic analysis.

  1. 6. Acoustic trapping for biomedical analysis

    Författare :Martin Wiklund; KTH; []
    Nyckelord :;

    Sammanfattning : .... LÄS MER

  3. 7. Spectra of elliptic operators and applications

    Författare :Medet Nursultanov; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Helmholtz and Maxwell s equations; functional calculus; electromagnetic waveguide; acoustic waveguide; Sturm-Liouville operator; singular potential; asymptotics of eigenvalues; point interactions.;

    Sammanfattning : In this thesis we consider several problems related to elliptic equations. Namely, we investigate Helmholtz and Maxwell's equations in Paper I and Sturm-Liouville spectral problem in Papers II,III. In Paper I we study time-harmonic electromagnetic and acoustic waveguide, modeled by an in�nite cylinder with a non-smooth cross section. LÄS MER

  4. 8. Acoustic characterization of orifices and perforated liners with flow and high-level acoustic excitation

    Författare :Lin Zhou; Hans Bodén; Wim De Roeck; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Bias Flow; Grazing Flow; Nonlinear Acoustics; Acoustic Impedance; Impedance Eduction; Single Mode Straightforward Method; Uncertainty Analysis; LEE; LNSE; Järnvägsgruppen - Ljud och vibrationer; Järnvägsgruppen - Ljud och vibrationer;

    Sammanfattning : This thesis is motivated by the need for noise control in aircraft engine with orifices and perforated liner. The presence of high-level acoustic excitation, different flow situations either bias flow, grazing flow or any combination in the aircraft engine, makes the acoustic behavior complex due to the interaction between sound and flow over the lined wall. LÄS MER

  5. 9. Numerical Methods for Aeroacoustic Analysis of Turbomachines

    Författare :Daniel Lindblad; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Stability Analysis; Acoustic Analogy; Tonal Noise; Nonreflecting Boundary Conditions; Duct Modes; Turbomachinery; Harmonic Balance; Ffowcs Williams - Hawkings; Time Sampling; Aliasing;

    Sammanfattning : Numerical simulations are important tools for developing new aircraft that can meet future needs. When numerical simulations are used to compute aircraft noise, a two-step procedure is often employed. In the first step, the noise sources are determined using, e.g. LÄS MER

  7. 10. Structure-acoustic analysis; finite element modelling and reduction methods

    Författare :Peter Davidsson; Byggnadsmekanik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Mechanical engineering; hydraulics; vacuum technology; vibration and acoustic engineering; Maskinteknik; hydraulik; vakuumteknik; vibrationer; akustik; low frequency range; building acoustics; lightweight structures; porous materials; modal reduction; substructuring; finite element analysis; structural acoustics; vibroacoustics; Structural dynamics;

    Sammanfattning : This thesis investigates structure-acoustic systems by use of finite element analysis. The systems studied here are limited to those that consist of an enclosed acoustic fluid cavity, which is coupled to a flexible structure and/or a porous sound absorbing material domain. LÄS MER