Search for dissertations about: "Acoustic Analogy"

Showing result 1 - 5 of 17 swedish dissertations containing the words Acoustic Analogy.

  2. 1. Numerical Simulations of Turbulent Flows at Widely Different Mach Numbers

    Author : Dragos Moroianu; Strömningsteknik; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; vibration and acoustic engineering; Maskinteknik; hydraulics; vacuum technology; Mechanical engineering; plasma; Energy research; Energiforskning; fluiddynamik; plasmas; Gaser; fluid dynamics; Gases; computational fluid dynamics; Acoustic; hydraulik; vakuumteknik; vibrationer; akustik; compressible flow;

    Abstract : The present thesis mainly focuses on the numerical simulation of the turbulent flow field and acoustics developed in different industrial applications. The study covers a large range of Mach numbers, starting from incompressible regimes and ending with a fully compressible flow. READ MORE

  4. 2. Shape Optimization for Acoustic Wave Propagation Problems

    Author : Rajitha Udawalpola; Martin Berggren; Pekka Neittaanmäki; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; shape optimization; design optimization; acoustic wave propagation; Helmholtz equation; Boundary Element Method; Finite Element Method; inverse problems; adjoint method; gradient-based optimization; Scientific Computing; Beräkningsvetenskap;

    Abstract : Boundary shape optimization is a technique to search for an optimal shape by modifying the boundary of a device with a pre-specified topology. We consider boundary shape optimization of acoustic horns in loudspeakers and brass wind instruments. READ MORE

  5. 3. Numerical Methods for Aeroacoustic Analysis of Turbomachinery

    Author : Daniel Lindblad; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Convective Ffowcs Williams - Hawkings Equation; Computational Aeroacoustics; Acoustic Analogy; Von Neumann Stability Analysis; Tonal Noise; CAA; Harmonic Balance Method; Counter Rotating Open Rotor;

    Abstract : Air transportation is today an integral part of many peoples life and it continuously grow to serve more of us in new and ingenious ways. There are however negative sides to this growth as well, such as increased noise around airports and more CO2 emissions, which must be addressed if aviation is to be part of a sustainable future. READ MORE

  6. 4. Numerical Methods for Aeroacoustic Analysis of Turbomachines

    Author : Daniel Lindblad; Chalmers tekniska högskola; []
    Keywords : 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;

    Abstract : 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. READ MORE

  7. 5. Numerical Techniques for Acoustic Modelling and Design of Brass Wind Instruments

    Author : Daniel Noreland; Bertil Gustafsson; Leif Abrahamsson; Björn Sjögreen; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Acoustic horn; brass wind instrument; loudspeaker; optimization; hybrid method; Numerical Analysis; Numerisk analys;

    Abstract : Acoustic horns are used in musical instruments and loudspeakers in order to provide an impedance match between an acoustic source and the surrounding air. The aim of this study is to develop numerical tools for the analysis and optimisation of such horns, with respect to their input impedance spectra. READ MORE