Sökning: "acoustic wave scattering"

Visar resultat 1 - 5 av 32 avhandlingar innehållade orden acoustic wave scattering.

1. 1. Wave Splitting in Direct and Inverse Scattering Problems

   Författare :Mats Gustafsson; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Maxwell equations; inverse problem; Electronics; inverse scattering; wave splitting; Elektronik;

   Sammanfattning : The focus of this thesis is on the use of wave splitting in electromagnetic direct and inverse scattering problems. Wave splitting offers a decomposition of wave fields into appropriate input and output wave constituents. LÄS MER

3. 2. 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

4. 3. Assessing precision and accuracy in acoustic scattering matrix measurements

   Författare :Luck Peerlings; Hans Bodén; Susann Boij; Avraham Hirschberg; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; aero-acoustics; sudden area expansion; in-duct acoustics; acoustic scattering matrix; impedance tube; uncertainty analysis; systematic errors; Vehicle and Maritime Engineering; Farkostteknik;

   Sammanfattning : Acoustic scattering matrices are used to characterize the influence of inline duct elements on the acoustic wave propagation in wave guides.When measuring the properties of these matrices, errors are always present in the results and need to be characterized to make valid statements on the correspondence between model predictions and measurements. LÄS MER

5. 4. Experimental Investigation of the Acoustic Properties of Perforate using Acoustic Three-Ports

   Författare :Shail A. Shah; Susann Boij; Hans Bodén; Wim De Roeck; KTH; []
   Nyckelord :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;

   Sammanfattning : 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. LÄS MER

7. 5. Acoustic separation of submicron particles in gaseous flows

   Författare :Ramin Imani Jajarmi; Laszlo Fuchs; Etienne Robert; Klas Engvall; Martin Wiklund; KTH; []
   Nyckelord :Acoustic; submicron particles; gaseous flows; separation; Engineering Mechanics; Teknisk mekanik;

   Sammanfattning : The separation of submicron particles suspended in gaseous flows is a problem of great importance and is the subject of sustained research efforts. This is motivated by several challenges presented by modern science and technology requiring high separation efficiencies for submicron particles. LÄS MER