Search for dissertations about: "Boundary parameter"

Showing result 1 - 5 of 162 swedish dissertations containing the words Boundary parameter.

2. 1. Experimental study on turbulent boundary-layer flows with wall transpiration

   Author : Marco Ferro; Jens Fransson; Bengt Fallenius; Joseph Klewicki; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Turbulent boundary layer; boundary-layer suction; boundary-layer blowing; wall-bounded turbulent flows; self-sustained turbulence; Engineering Mechanics; Teknisk mekanik;

   Abstract : Wall transpiration, in the form of wall-normal suction or blowing through a permeable wall, is a relatively simple and effective technique to control the behaviour of a boundary layer. For its potential applications for laminar-turbulent transition and separation delay (suction) or for turbulent drag reduction and thermal protection (blowing), wall transpiration has over the past decades been the topic of a significant amount of studies. READ MORE

4. 2. Simulations of turbulent boundary layers with suction and pressure gradients

   Author : Alexandra Bobke; Philipp Schlatter; Ramis Örlü; Ayse Gul Gungor; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; boundary layers; near-wall turbulence; history effects; asymptotic suction boundary layers; large-eddy simulation;

   Abstract : The focus of the present licentiate thesis is on the effect of suction and pressure gradients on turbulent boundary-layer flows, which are investigated separately through performing numerical simulations.The first part aims at assessing history and development effects on adverse pressure-gradient (APG) turbulent boundary layers (TBL). READ MORE

5. 3. 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

6. 4. Two Problems in non-linear PDE’s with Phase Transitions

   Author : Karl Jonsson; Henrik Shahgholian; Tomas Sjödin; KTH; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Conductivity jump; Free boundary problem; Quasilinear elliptic equation; Mathematical techniques; Nonlinear analysis; Free boundary; Free-boundary problems; Quasi-linear elliptic; Quasilinear elliptic equations; Hele-Shaw flow; non-local; implicit function theorem; Heterogeneous Multi Scale; HMM; Finite Element; FEM; FE; Mathematics; Matematik;

   Abstract : This thesis is in the field of non-linear partial differential equations (PDE), focusing on problems which show some type of phase-transition. A single phase Hele-Shaw flow models a Newtoninan fluid which is being injected in the space between two narrowly separated parallel planes. READ MORE

7. 5. Experimental studies of turbulent boundary layer separation and control

   Author : Kristian Angele; KTH; []
   Keywords : turbulence; boundary layer; separition; adverse pressure graddient;

   Abstract : The object ofthe present work is to experimentally study thecase ofa turbulent boundary layer subjected to an AdversePressure Gradient (APG) with separation and reattachment. Thisconstitutes a good test case for advanced turbulence modeling. READ MORE