Search for dissertations about: "Lined ducts"

Found 3 swedish dissertations containing the words Lined ducts.

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. Optimal damping and slow sound in ducts

   Author : Zhe Zhang; Mats Åbom; Hans Bodén; Lars Enghardt; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Vehicle and Maritime Engineering; Farkostteknik;

   Abstract : The thesis is dedicated to expanding knowledge on two duct acoustic issues including: 1) the optimal damping of low frequency sound and 2) the development and application of ‘slow sound’.To address the first issue, the ‘Cremer impedance’ proposed more than half a century ago has been revisited and further developed. READ MORE