Search for dissertations about: "roughness control"

Showing result 11 - 15 of 75 swedish dissertations containing the words roughness control.

2. 11. 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

4. 12. Grafted Molecular Layers for Control of Surface Properties

   Author : Gunnar Dunér; Andra Dédinaité; Stefan Zauscher; KTH; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES;

   Abstract : The goal of this thesis work was to develop responsive surface grafted brushlayers for control of surface properties and to gain insights in the molecular mechanisms that control these properties. Three types of grafted layers were investigated, as outlined below. READ MORE

5. 13. On stability and receptivity of boundary-layer flows

   Author : Nima Shahriari; Ardeshir Hanifi; Dan S. Henningson; Peter J. Schmid; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; boundary layer receptivity; acoustic receptivity; swept-wing flow; crossflow vortices; roughness element; global stability analysis; direct numerical simulation; plasma actuator; Engineering Mechanics; Teknisk mekanik;

   Abstract : This work is concerned with stability and receptivity analysis as well as studies on control of the laminar-turbulent transition in boundary-layer flows through direct numerical simulations. Various flow configurations are considered to address flow around straight and swept wings. READ MORE

6. 14. Terrain machine learning

   Author : Viktor Wiberg; Martin Servin; Tomas Nordfjell; Eddie Wadbro; Todor Stoyanov; Umeå universitet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; multibody dynamics simulation; rough terrain vehicle; autonomous vehicles; robotics control; discrete element method; sim-to-real; reinforcement learning; fysik; Physics;

   Abstract : The use of heavy vehicles in rough terrain is vital in the industry but has negative implications for the climate and ecosystem. In addition, the demand for improved efficiency underscores the need to enhance these vehicles' navigation capabilities. READ MORE

7. 15. Methods for Characterisation of Pressing Die Surfaces

   Author : Johan C Berglund; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; finish milling; scale-sensitive fractal analysis; surface characterisation; polishing; functional correlation; : pressing dies; functional filtration; surface roughness; functional surface;

   Abstract : Design and manufacture of dies and moulds is a critical aspect of many production systems since the manufacturing and try-out of new dies and moulds often is essential in determining the lead-time and quality of a new production system. In the automotive industry, many new car models are introduced each year and for each of these models, a new set of pressing dies has to be designed and manufactured. READ MORE