Sökning: "Impedance Eduction"

Hittade 2 avhandlingar innehållade orden Impedance Eduction.

  1. 1. 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

  3. 2. Innovative noise control in ducts

    Författare :Maaz Farooqui; Mats Åbom; Hans Bodén; Tamer Elnady; Jeong-Guon Ih; KTH; []
    Nyckelord :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;

    Sammanfattning : 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. LÄS MER