Search for dissertations about: "boundary elements methods"

Showing result 1 - 5 of 62 swedish dissertations containing the words boundary elements methods.

2. 1. Time Domain Boundary Element Methods for Acoustic Scattering

   Author : Georgios Natsiopoulos; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; time domain; curved surface; room acoustics; boss model; boundary element method; regularization; transient; Hermite interpolation; hypersingular; acoustic scattering; vector potential;

   Abstract : In room acoustics, numerical computation of scattering phenomena is an important subject, since it is needed to accurately predict the influence of reflectors, the audience, balconies, etc, on the perceived acoustic quality of auditoria. The large physical volumes of auditoria and the wide frequency content of music and speech, together with the complicated geometries involved however, makes predictions in room acoustics a challenging task from a computational point of view. READ MORE

4. 2. Wave Splitting and Effective Boundary Conditions for Structural Elements

   Author : Martin Johansson; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; approximate boundary condition; Mindlin plate; Timoshenko beam; thin plates; cylindrical coordinates; series approximation; wave splitting; dispersion; fluid-loaded plate; Biot;

   Abstract : The subject of this thesis is twofold. The first part concerns the wave splitting of structural elements. The second part concerns approximate boundary conditions for fluid-loaded thin plates. Wave splitting is a mathematical tool for the formulation of scattering problems in the time domain that aims at solving inverse problems, e. READ MORE

5. 3. Wet clutch tribological performance optimization methods

   Author : Pär Marklund; Luleå tekniska universitet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Machine Elements; Maskinelement;

   Abstract : Wet clutches are used in a variety of machinery such as in vehicles where they are used to distribute torque in the drivetrains. Clutches can be located in automatic transmissions or in limited slip differentials. READ MORE

6. 4. Boundary layer streaks as a novel laminar flow control method

   Author : Sohrab Sattarzadeh Shirvan; Jens H. M. Fransson; Edward B. White; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; boundary layer stability; laminar to turbulent transition; laminar flow control; drag reduction; Tollmien-Schlichting waves; oblique waves; streaky boundary layers; miniature vortex generators; discrete suction;

   Abstract : A novel laminar flow control based on generation of spanwise mean velocity gradients (SVG) in a flat plate boundary layer is investigated where disturbances of different types are introduced in the wall-bounded shear layer. The experimental investigations are aimed at; (i) generating stable and steady streamwise streaks in the boundary layer which set up spanwise gradients in the mean flow, and (ii) attenuating disturbance energy growth in the streaky boundary layers and hence delaying the onset of turbulence transition. READ MORE

7. 5. Numerical methods for waveguide modelling

   Author : Christer Johansson; Björn Engquist; Per Lötstedt; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Waveguide; finite element; hp-adaptivity; helmholtz; maxwell; Numerical analysis; Numerisk analys;

   Abstract : Waveguides are used to transmit electromagnetic signals. Their geometry is typically long and slender. This particular shape can be used in the design of efficient computational methods. Only special modes are transmitted and eigenvalue and eigenvector analysis becomes important. READ MORE