Search for dissertations about: "surfaces roughness"

Showing result 16 - 20 of 200 swedish dissertations containing the words surfaces roughness.

2. 16. Measurements and Prediction of Friction Drag of Rough Surfaces

   Author : Bercelay Niebles Atencio; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; PIV; RANS; Turbulent Boundary Layers; Flat Plate; Resolved CFD; Hydrodynamics; Roughness Function; Wall Functions; Rotating Disk;

   Abstract : Owing to the increased sea transportation of goods, the environmental impacts of this activity are becoming more and more important, since a ship experiences resistance that directly affects its performance and fuel consumption. The growth of marine organisms (fouling) on ship hulls increases the roughness of the hull surface, which in turn causes a rise in ship resistance with a consequent increase in fuel consumption and greenhouse emissions of up to 40%. READ MORE

4. 17. Homogenization of some new mathematical models in lubrication theory

   Author : Afonso Fernando Tsandzana; Peter Wall; Lars- Erik Persson; John Fabricius; Anders Holmbom; Luleå tekniska universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; lubrication theory; homogenization theory; Reynolds equation; cavitation; surfaces roughness; Stokes equation; Matematik; Mathematics;

   Abstract : We consider mathematical modeling of thin film flow between two rough surfaces which are in relative motion. For example such flows take place in different kinds of bearings and gears when a lubricant is used to reduce friction and wear between the surfaces. READ MORE

5. 18. Roughness lengths and roughness sublayer corrections in partly forested regions

   Author : Meelis Mölder; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Earth sciences; flux parameterisation; profile measurements; radiation temperature; displacementheight; barley; pasture; Geovetenskap; Earth sciences; Geovetenskap; Hydrology; hydrologi;

   Abstract : Questions related to water resources management and climate change at regional to global scales have inspired research about processes governing exchange of water, heat and carbon between land and atmosphere. The concept of roughness length is fundamental in deduction of bulk transfer relations from the generally accepted Monin-Obukhov similarity theory for this exchange. READ MORE

6. 19. Hydrodynamic lubrication of rough surfaces

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

   Abstract : Interacting surfaces are frequently found in mechanical systems and components. A lubricant is often added between the surfaces to separate them from mechanical contact in order to increase life and performance of the contacting surfaces. In this work various aspects of hydrodynamic lubrication are investigated theoretically. READ MORE

7. 20. Surfaces of Honed Cylinder Liners

   Author : Zlate Dimkovski; B.-G. Rosén; Mohamed El-Mansori; Högskolan i Halmstad; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Honing; Characterisation; Blechmantel; Groove Parameters; Quality Control; Oil Consumption; Wear; Friction; Mixed Lubrication Simulation; Surface engineering; Ytbehandlingsteknik;

   Abstract : Cylinder liner surfaces are often on the agenda of engine developers because of their large influence on the frictional losses, oil consumption and emissions of internal combustion engines. Improving the liner function involves not only manufacturing new surfaces and checking their function but also characterising them as a necessary intermediate step for better understanding of the changes made. READ MORE