Sökning: "Boundary integral equation method"

Visar resultat 21 - 25 av 30 avhandlingar innehållade orden Boundary integral equation method.

1. 21. Modelling of ultrasonic scattering from a crack in a pipe

   Författare :Jacob Rubenson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Non-Destructive Testing; Cylindrical Geometry; Pipe; Crack; Wave propagation;

   Sammanfattning : This thesis considers elastic wave scattering in an infinitely long cylindrical pipe with an infinitely long internal axial crack. The method used in this thesis is called a hypersingular integral equation method since it starts with an integral representation and by using the Green's tensor of the pipe it can be manipulated to a hypersingular equation for the crack-opening displacement (COD). LÄS MER

3. 22. Computational methods for microfluidics

   Författare :Ludvig af Klinteberg; Anna-Karin Tornberg; Peter Hansbo; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : This thesis is concerned with computational methods for fluid flows on the microscale, also known as microfluidics. This is motivated by current research in biological physics and miniaturization technology, where there is a need to understand complex flows involving microscale structures. Numerical simulations are an important tool for doing this. LÄS MER

4. 23. Numerical Solution of Ill-posed Cauchy Problems for Parabolic Equations

   Författare :Zohreh Ranjbar; Lars Eldén; Per Christian Hansen; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; MATHEMATICS; MATEMATIK;

   Sammanfattning : Ill-posed mathematical problem occur in many interesting scientific and engineering applications. The solution of such a problem, if it exists, may not depend continuously on the observed data. For computing a stable approximate solution it is necessary to apply a regularization method. LÄS MER

5. 24. Sound propagation from sustainable ground vehicles : from aeroacoustic sources to urban noise

   Författare :Nicolas Pignier; Ciarán O'Reilly; Susann Boij; Gwenael Gabard; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; sound propagation; sound generation; ground vehicle; aeroacoustics; aerodynamics; Kirchhoff approximation; detached eddy simulation; Ffowcs Williams and Hawkings; ljudutberdning; ljudalstring; markfordon; aeroakustik; aerodynamik; Kirchhoff approximation; detached eddy simulation; Ffowcs Williams and Hawkings; Vehicle and Maritime Engineering; Farkostteknik; Engineering Mechanics; Teknisk mekanik;

   Sammanfattning : Transportation is the main source of environmental noise in Europe, with an estimated 125 million people affected by excessive noise levels from road traffic, causing a burden of noise related diseases and having a substantial economic impact on society. In order to reduce exposure to high levels of traffic noise, two approaches are the topic of extensive research: preventing sound from propagating from roads and railways using for example noise barriers, and reducing the sources of noise themselves. LÄS MER

7. 25. Pressure-driven flows in thin and porous domains

   Författare :Elena Haller; Peter Wall; John Fabricius; Johan Byström; Eduard Marušic-Paloka; Luleå tekniska universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Applied Mathematics; Tillämpad matematik;

   Sammanfattning : The present thesis is devoted to the derivation of Darcy's law for incompressible viscous fluid flows in perforated and thin domains by means of homogenization techniques.  The problem of describing asymptotic flows in porous/thin domains occurs in the study of various physical phenomena such as filtration in sandy soils, blood circulation in capillaries, lubrication and heationg/cooling processes. LÄS MER