Sökning: "Bias Flow"

Visar resultat 1 - 5 av 64 avhandlingar innehållade orden Bias Flow.

  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. A Study of Using Pulsed Neutron Activation for Accurate Measurements of Water Flow in Pipes

    Författare :Per Lindén; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; pulsed neutron activation; turbulent flow; neural networks; pipe flow; flow measurements; eddy diffusion; time averaging;

    Sammanfattning : The objectives of this work were 1) to investigate the performance of the pulsed neutron activation (PNA) method for determination of mass flow of water in pipes, and 2) to improve the accuracy such that an error less than 1% become possible with the PNA method. The ultimate purpose is to develop this method into a high-accuracy portable and non-intrusive flow-meter that easily can be used as a calibration tool at a number of field applications, e. LÄS MER

  4. 3. Theoretical and experimental studies of the flux-flow type Josephson oscillator

    Författare :Yongming Zhang; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Nb NbOx PbBi tunnel junction; resistive loading; effect of self-field; resonant fluxion motion; velocity-matching step; chaotic phenomena; SIS detector; optimum bias feed; uniform bias feed; open-circuit boundary condition; perturbed sine-Gordon qeuation; reactive ion beam oxidation; effect of damping; one dimensional Josephson junction; flux-flow type Josephson oscillator;

    Sammanfattning : .... LÄS MER

  5. 4. Experimental Determination of Aeracoustic Sources in Low Mach Number Internal Flows

    Författare :Andreas Holmberg; Hans Bodén; Lars Enghardt; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Aeracoustics; ducts; N-ports; scattering matrix; wave decomposition; source determination; over-determination; flow noise; fluid-acoustic interaction; fluid-structure-acoustic interaction; wave number; T-junction; power balance; grazing-bias flow; Acoustics; Akustik; Vehicle engineering; Farkostteknik;

    Sammanfattning : In this thesis, the in-duct experimental methods for determining aeroacoustic N-ports of in-duct elements are discussed and improved. The scattering matrix determination methods and the related wave decomposition methods are evaluated from measurements in an empty duct carrying a mean flow. LÄS MER

  7. 5. Investigation of perforated mufflers and plates

    Författare :Ying Guo; Mast Abom; Ragnar Glav; KTH; []
    Nyckelord :sound; perforated; micro-perforated; muffler; flow; hole; impedance; model; experiment;

    Sammanfattning :     Mufflers are used in for instance exhaust system of cars or trucks to reduce noise. Perforated pipes are one of the main components of modern mufflers. To study acoustic properties of mufflers with perforated pipe is one of the main targets of this thesis. LÄS MER