Sökning: "Near-field Acoustics"

Visar resultat 1 - 5 av 12 avhandlingar innehållade orden Near-field Acoustics.

  1. 1. Near-Field Study of Multiple Interacting Jets : Confluent Jets

    Författare :Shahriar Ghahremanian; Bahram Moshfegh; Linköpings universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Multiple interacting jets; confluent jets; axisymmetric round jet; Low Reynolds number jet; Particle Image Velocimetry PIV ; Laser Doppler Anemometry LDA ; Hot-Wire anemometry HWA ; RANS turbulence models; SST ? − ?; Low Reynolds ? − ?; Response Surface Method;

    Sammanfattning : This thesis deals with the near-field of confluent jets, which can be of interest in many engineering applications such as design of a ventilation supply device. The physical effect of interaction between multiple closely spaced jets is studied using experimental and numerical methods. LÄS MER

  3. 2. Single layer near-field acoustic imaging in space-invariant reflective environments

    Författare :Elias Zea; Ines Lopez Arteaga; Efren Fernandez-Grande; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; near-field acoustic holography; field separation techniques; single layer; space-invariance; reflective envirionments; närfält akustisk holografi; fältseparationstekniker; enkelt lager; utrymmes invarians; reflekterande miljöer; Vehicle and Maritime Engineering; Farkostteknik;

    Sammanfattning : The visualization of optical fields, or widely known as photography, is a common practice that can also be applied to acoustic fields. No less than three decades of research in acoustic imaging demonstrate its potential and relevance in plenty applications such as sound source identification and localization, as well as characterization of noise generation mechanisms. LÄS MER

  4. 3. Large Eddy Simulation of Turbulent Compressible Jets

    Författare :Bernhard Semlitsch; Mihai Mihaescu; Laszlo Fuchs; Paul G. Tucker; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Compressible Flow; Large Eddy Simulation; Acoustic Noise Generation; Near-field Acoustics; Flow Control; Optimization; Modal Flow Decomposition; Engineering Mechanics; Teknisk mekanik;

    Sammanfattning : Acoustic noise pollution is an environmental aggressor in everyday life. Aero- dynamically generated noise annoys and was linked with health issues. It may be caused by high-speed turbulent free flows (e.g. LÄS MER

  5. 4. Measurement and evaluation of near-field spray kinematics for nozzles with asymmetrical inlet geometries

    Författare :Mohammad Nikouei; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Nozzle Geometry; Spray Dynamics; Spray Velocity; Diesel Spray; Ballistic Imaging;

    Sammanfattning : In diesel engines, fuel injection parameters have a commanding effect on mixing and combustion quality. This research aims to enhance the fundamental knowledge of fuel sprays and their primary break-up. In addition, this research provides statistical data to validate simulation models and improve the prediction accuracy in mixing and combustion. LÄS MER

  7. 5. Sound field separation with microphone arrays

    Författare :Elias Zea; Ines Lopez Arteaga; Mats Åbom; Leif Kari; Jean-Hugh Thomas; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Sound field separation; Microphone arrays; Near-field acoustic holography; Reflecting surfaces; Railway rolling noise; Vehicle and Maritime Engineering; Farkostteknik;

    Sammanfattning : Sound field analysis is a fundamental tool in the design, manufacturing, testing and diagnosis of machines and transportation means, as well as the legislations that regulate noise levels in order to minimize environmental pollution. Customary solutions to the problem of sound field analysis are microphone array technologies such as near-field acoustic holography (NAH) and beamforming. LÄS MER