Sökning: "Rotating surface"

Visar resultat 16 - 20 av 83 avhandlingar innehållade orden Rotating surface.

1. 16. The rotating-disk boundary-layer flow studied through numerical simulations

   Författare :Ellinor Appelquist; Philipp Schlatter; Henrik Alfredsson; Rebecca Lingwood; Benoît Pier; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; laminar-turbulent transition; convective instability; absolute instability; crossflow instability; direct numerical simulations; Fysik; Physics;

   Sammanfattning : This thesis deals with the instabilities of the incompressible boundary-layer flow thatis induced by a disk rotating in otherwise still fluid. The results presented include bothwork in the linear and nonlinear regime and are derived from direct numerical sim-ulations (DNS). LÄS MER

3. 17. Aerodynamic design framework for low-pressure compression systems

   Författare :Marcus Lejon; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; manufacturing variations; optimization; stage matching; tip clearance; validation; Turbomachinery; CFD; surface roughness; compressor;

   Sammanfattning : Aircraft engine manufacturers strive to improve current state of the art designs through continuous development efforts. By improving existing designs and exploring new alternatives, the goal is to reduce the fuel consumption - a topic of high relevance due to the remarkable growth rate of air traffc. LÄS MER

4. 18. Measurements and Prediction of Friction Drag of Rough Surfaces

   Författare :Bercelay Niebles Atencio; Chalmers tekniska högskola; []
   Nyckelord :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;

   Sammanfattning : 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%. LÄS MER

5. 19. Silicone Rubber Insulators: Impacts of Material Formulation in Coastal Environment

   Författare :Tomas G Gustavsson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; surface characterization; aging; filler level; outdoor insulation; leakage current measurements; material formulation; silicone rubber; polymeric insulators; coastal environment; polydimethylsiloxane PDMS ;

   Sammanfattning : This thesis deals with influences of material formulation on the performance of silicone rubber high voltage insulators in a coastal environment. Samples and insulators with known differences in material compositions have been used in this task. In the first step, a screening test with cylindrical samples was initiated. LÄS MER

7. 20. Adding utility to carbon materials: introducing dopants using highly soluble metal salts and functionalizing surfaces via bromomethylation

   Författare :Samuel Joseph Fretz; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Carbon; Doping; Surface functionalization; Li-S batteries; Fuel cell;

   Sammanfattning : Carbon-based materials have received intense research interest over the past few decades due to their outstanding combination of properties including porosity, non-toxicity, chemical inertness, low density, and electrical conductivity, which has allowed them to find a wide array of applications including supercapacitors, batteries, CO2 capture, fuel cells and catalysis. To expand their utility, a variety of techniques have been developed to enhance their reactivity and functionality. LÄS MER