Search for dissertations about: "mufflers"

Showing result 1 - 5 of 7 swedish dissertations containing the word mufflers.

  2. 1. Modelling and Characterization of Perforates in Lined Ducts and Mufflers

    Author : Tamer Elnady; KTH; []
    Keywords : Perforates; Liners; Acoustic impedance; Hot stream liners; Hard splices; Mufflers; Lined ducts; Collocation; Flow duct.;

    Abstract : Increased national and international travel over the lastdecades has caused an increase in the global number ofpassengers using different means of transportation. Greateffort is being directed to improving the noisy environment inthe residential community. READ MORE

  4. 2. 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

  5. 3. Investigation of perforated mufflers and plates

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

    Abstract :     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. READ MORE

  6. 4. Investigation and Optimization of the Acoustic Performance of Exhaust Systems

    Author : Sara Elsaadany; Mats Åbom; Ray Kirby; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Exhaust systems; noise; pressure drop; 1D models; perforated mufflers; after treatment devices; optimization;

    Abstract : There is a strong competition among automotive manufacturers to reduce the radiated noise levels. One important source is the engine exhaust where the main noise control strategy is by using efficient mufflers. READ MORE

  7. 5. Analysis, Control, and Design Optimization of Engineering Mechanics Systems

    Author : Esubalewe Lakie Yedeg; Martin Berggren; Eddie Wadbro; Anton Evgrafov; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Topology optimization; Helmholtz equation; acoustic impedance; anisotropic filter; thin structures; finite element method; Nitsche-type method; interface problem; Optimal control; adjoint method; business data processing; administrativ databehandling;

    Abstract : This thesis considers applications of gradient-based optimization algorithms to the design and control of some mechanics systems. The material distribution approach to topology optimization is applied to design two different acoustic devices, a reactive muffler and an acoustic horn, and optimization is used to control a ball pitching robot. READ MORE