Sökning: "surface boundary layers"

Visar resultat 16 - 20 av 89 avhandlingar innehållade orden surface boundary layers.

1. 16. Receptivity, Stability and Sensitivity analysis of two- and three-dimensional flows

   Författare :Guillaume Chauvat; Ardeshir Hanifi; Dan S. Henningson; Ulrich Rist; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; boundary-layers; stability; receptivity; sensitivity; transition; mode decomposition; Engineering Mechanics; Teknisk mekanik;

   Sammanfattning : This work deals with various aspects of boundary-layer stability. Modal and non-modal approaches are first used in the study of the global stability of a jet in crossflow. LÄS MER

3. 17. The Friction between Paper Surfaces

   Författare :Niklas Garoff; KTH; []
   Nyckelord :friction; fibers; boundary lubrication; adhesion; capillary condensation; surface forces; chemcial analysis; x-ray photoelectron spectroscopy; atomic force microscope;

   Sammanfattning : The main objective for the work described in this PhD thesiswas to formulate a friction model to characterize thefrictional behavior of paper. More specifically, the modelshould explain a phenomenon that is typical for paper grades,viz.: that the level of paper-to-paper friction is dependent onthe direction and the number of previous slides. LÄS MER

4. 18. An experimental study on streamwise streaks in transitional boundary layers

   Författare :Shahab Shahinfar; Jens Fransson; Yury Kachanov; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : The present experimental study focuses on two topics, a passive transition-delay method for different types of wave disturbances and the effect of free-stream turbulence characteristics on boundary layer transition over a at plate. In the investigations, hot-wire anemometry was employed and the experiments were performed in a well-controlled wind tunnel facility. LÄS MER

5. 19. Hydrogen in ultrathin vanadium layers

   Författare :Gabriella Andersson; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; Fysik; Physics; Fysik; Fysik; Physics;

   Sammanfattning : The influence of elastic boundary conditions on the thermodynamics of hydrogen in vanadium were investigated using resistometry, x-ray diffraction and nuclear reaction analysis. To provide varying lattice strain states Mo/V (110) and Fe/V (001) superlattices with thickness L of individual layers in the range 3-16 monolayers (ML) were used. LÄS MER

7. 20. Biolubricants and Biolubrication

   Författare :Min Wang; Andra Dėdinaitė; Per Claesson; Esben Thormann; Holmberg Krister; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Hyaluronan; Phospholipid; Lubricin; Cartilage Oligomeric Matrix Protein; COMP; Adsorption; Surface Force; Friction; Biolubrication; Boundary Lubrication; Load Bearing Capacity; Synergistic Effects; DLS; QCM-D; AFM.; Hyaluronan; Fosfolipid; Lubricin; Cartilage Oligomeric Matrix Protein; COMP; Adsorption; Ytkraft; Friktion; Biologisk smörjning; Gränsskiktssmörjning; Lastbärande förmåga; Synergieffekter; DLS; QCM-D; AFM.; Kemi; Chemistry;

   Sammanfattning : The main objective of this thesis work was to gain understanding of the principles of biolubrication, focusing on synergistic effects between biolubricants. To this end surface force and friction measurements were carried out by means of Atomic Force Microscopy, using hydrophilic and hydrophobic model surfaces in salt solutions of high ionic strength (≈ 150 mM) in presence of different biolubricants. LÄS MER