Search for dissertations about: "Grazing flow"

Showing result 1 - 5 of 22 swedish dissertations containing the words Grazing flow.

2. 1. Analysis of Acoustic Absorption with Extended Liner Reaction and Grazing Flow

   Author : Anna Färm; Mats Åbom; Lars Enghardt; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Sound absorption; acoustic lining; non-locally reacting; boundary layer; grazing flow; sound field; transfer matrix method;

   Abstract : Acoustic absorbing liners are efficient and commonly used measures to reduce sound levels in many fields of application. The sound reducingperformance of the liners is dependent on the acoustic state, defined by e.g. the flow and sound field interacting with the liner. READ MORE

4. 2. 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

5. 3. 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

6. 4. Picophytoplankton seasonal dynamics in the Baltic Sea

   Author : Javier Alegria Zufía; Hanna Farnelid; Catherine Legrand; Nathan Ahlgren; Linnéuniversitetet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; picophytoplankton; Synechococcus; picoeukaryote; phycoerythrin; phycocyanin; ammonium; nitrate; 16S rDNA; flow cytometry; grazing; viral lysis; seasonality; Akvatisk ekologi; Aquatic Ecology;

   Abstract : Picophytoplankton (15°C there was a preference for ammonium over nitrate. Clade A/B dominated the SYN community, except during summer at the coastal station when low nitrate and warm temperatures promoted S5.2 dominance. Grazing was observed to control SYN and PPE abundances and had an effect on the SYN community structure. READ MORE

7. 5. 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