Sökning: "Plane wave expansion method"

Visar resultat 1 - 5 av 10 avhandlingar innehållade orden Plane wave expansion method.

  1. 1. Methods and techniques for precise and accurate in-duct aero-acoustic measurements : Application to the area expansion

    Författare :Luck Peerlings; Susann Boij; Hans Bodén; Yves Aurégan; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Area-expansion; Scattering matrix; Multi-microphone method; Engineering Mechanics; Teknisk mekanik;

    Sammanfattning : During the design and commissioning of combustion equipment, combustion associated instabilities are commonly encountered. These thermo-acoustic instabilities can cause undesirable noise, vibrations, local thermal and mechanical stresses in the combustor and are prominent in lean combustion. LÄS MER

  3. 2. Computational methods for the analysis and design of photonic bandgap structures

    Författare :Min Qiu; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Photonic crystal; Photonic bandgap; Numerical analysis; Optimal design; Finite-difference time-domain method; Plane wave expansion method; Electrical engineering; electronics and photonics; Elektroteknik; elektronik och fotonik;

    Sammanfattning : In the present thesis, computational methods for theanalysis and design of photonic bandgap structure areconsidered. Many numerical methods have been used to study suchstructures. Among them, the plane wave expansion method is veryoften used. LÄS MER

  4. 3. Carbon-nanofibre-based tunable photonic crystals

    Författare :Robert Rehammar; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; transfer matrix; carbon nanofibre; fdtd; Photonic crystal; PECVD; plane wave expansion; tunable;

    Sammanfattning : Photonic crystals are materials with periodically varying refractive indices. In conventional photonic crystal design it is hard to achieve tunable structures in the visible range. That is, structures with changeable optical properties. LÄS MER

  5. 4. Acoustic, Thermal and Non-thermal Dynamics in Condensed Matter Studied by Time-Resolved X-ray Diffraction

    Författare :Carl Ekström; Atomfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; X-ray diffraction; Time-resolved; Ultrafast; Non-thermal melting; Thermal conductivity; Pressure wave; Opto-acoustic transducer; Fysicumarkivet A:2020:Ekström;

    Sammanfattning : The method of using short laser and X-ray pulses to investigate dynamics in materials (pump-probe) has been used for several decades. This thesis presents work that was carried out using these sources of light to reveal acoustic, thermal and non-thermal dynamics. LÄS MER

  7. 5. Wave Modelling Techniques for Medium and High Frequency Vibroacoustic Analysis Including Porous Materials

    Författare :Hao Liu; Svante Finnveden; Ines Lopez Arteaga; Mohamed Ichchou; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : Numerical methods based on wave modelling are explored for the vibroacoustic analysis of wave propagation, sound transmission and interior noise in vehicles and buildings at medium and high frequencies. The presence of sound absorbing porous materials in practical engineering structures is also considered. LÄS MER