Search for dissertations about: "roughness height"

Showing result 1 - 5 of 31 swedish dissertations containing the words roughness height.

2. 1. Characterization of Different Interface Types for HVDC Extruded Cable Applications

   Author : Espen Doedens; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; polymer surfaces; cable peelings; HVDC; Roughness; Charge injection; XLPE; Field enhancement factors; Schottky injection; DC breakdown; Voltage decay; interfaces; Fowler-Nordheim injection; extruded cable; Roughness assisted charge injection.; Charge decay;

   Abstract : In extruded HVDC cable systems a variety of interface types can be found, and the interfacial properties depend on the application within the system. Such applications can be joints, terminations or the cable itself and they will all have different material combinations and manufacturing methods. READ MORE

4. 2. 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

5. 3. The Enemy Below - Adhesion and Friction of Ship Hull Fouling

   Author : Dinis Oliveira; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; ship resistance; in-water hull cleaning; roughness; biofouling; hull grooming; frictional resistance; adhesion strength; turbulent boundary layer; hull form factor;

   Abstract : Below the waterline, commercial ships are good targets for marine organisms to attach and proliferate, a problem commonly known as biofouling. A fouled hull means higher hydrodynamic resistance, which can result in significant fuel penalties. READ MORE

6. 4. Effects of free-stream turbulence and three-dimensional roughness on boundary layer transition

   Author : Santhosh Babu Mamidala; Jens H. M. Fransson; Bengt E. G. Fallenius; Jonathan Morrison; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; boundary-layer transition; intermittency; free-stream turbulence; electret microphones; isolated roughness; sinuous instability; varicose instability; Engineering Mechanics; Teknisk mekanik;

   Abstract : External disturbances such as free-stream turbulence (FST), and isolated three-dimensional roughness are strong disturbance sources to the laminar boundary layers (BLs), which can lead to a rapid transition to turbulence. The transition process eventuates to increase in skin-friction coefficient and heat transfer rate and hence, both of the aforementioned disturbance sources have practical importance. READ MORE

7. 5. A study on Electron Beam Melted Ti-6Al-4V

   Author : Adnan Safdar; Hållfasthetslära; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Ti-6Al-4V; Electron beam melting; Microstructures; Surface roughness; phase filed modelling.;

   Abstract : The work presented in this dissertation is concerned with the microstructures and surface roughness of test slabs of Ti-6Al-4V produced by one of powder based Additive Manufacturing (AM) technique namely electron beam melting (EBM). The effects of process parameters of a EBM system and geometry factors of a EBM build such as slabs’ thickness and height etc. READ MORE