Search for dissertations about: "impedance matrix"

Showing result 1 - 5 of 32 swedish dissertations containing the words impedance matrix.

  2. 1. Assessing precision and accuracy in acoustic scattering matrix measurements

    Author : Luck Peerlings; Hans Bodén; Susann Boij; Avraham Hirschberg; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; aero-acoustics; sudden area expansion; in-duct acoustics; acoustic scattering matrix; impedance tube; uncertainty analysis; systematic errors; Vehicle and Maritime Engineering; Farkostteknik;

    Abstract : Acoustic scattering matrices are used to characterize the influence of inline duct elements on the acoustic wave propagation in wave guides.When measuring the properties of these matrices, errors are always present in the results and need to be characterized to make valid statements on the correspondence between model predictions and measurements. READ MORE

  4. 2. Experimental Investigation of the Acoustic Properties of Perforate using Acoustic Three-Ports

    Author : Shail A. Shah; Susann Boij; Hans Bodén; Wim De Roeck; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Duct Acoustics; Acoustical Three-port; Perforated plate; Transfer Impedance; Scattering Matrix; Grazing Flow; High-level Excitation; Non-linear effects; Flow-Acoustic Interaction; Rectangular T-Junction; Farkostteknik; Vehicle and Maritime Engineering;

    Abstract : This thesis discusses the aero-acoustic characterisation of a perforate sample using a three-port technique. A rectangular T-junction with a flush mounted perforated sample at the intersection form the acoustical three-port. READ MORE

  5. 3. Acoustic characterization of orifices and perforated liners with flow and high-level acoustic excitation

    Author : Lin Zhou; Hans Bodén; Wim De Roeck; KTH; []
    Keywords : 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;

    Abstract : 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. READ MORE

  6. 4. Innovative noise control in ducts

    Author : Maaz Farooqui; Mats Åbom; Hans Bodén; Tamer Elnady; Jeong-Guon Ih; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Locally resonant materials; slow sound; acoustic impedance; metallic foam; low frequency noise; mufflers; lined ducts; grazing flow; flow duct; impedance eduction.; Vehicle and Maritime Engineering; Farkostteknik;

    Abstract : The objective of this doctoral thesis is to study three different innovative noise control techniques in ducts namely: acoustic metamaterials, porous absorbers and microperforates. There has been a lot of research done on all these three topics in the context of duct acoustics. READ MORE

  7. 5. Voltage Dip (Sag) Estimation in Power Systems based on Stochastic Assessment and Optimal Monitoring

    Author : Gabriel Olguin; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; power quality; symmetr?cal components; stochastic methods; impedance matrix; voltage dips; integer optimisation; power systems; short-circuit faults; voltage sags;

    Abstract : This dissertation deals with the statistical characterization of the performance of power systems in terms of voltage dips (sags). It presents a method named voltage dip estimation that extends monitoring results to buses not being monitored. READ MORE