Sökning: "Aerodynamic roughness"

Visar resultat 1 - 5 av 7 avhandlingar innehållade orden Aerodynamic roughness.

  1. 1. 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

  3. 2. Land surface heat exchange over snow and frozen soil

    Författare :David Gustafsson; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Surface energy balance; Snow; Boreal forest; SVAT models; Eddy-correlation Measurements; Latent heat flux; Sensible heat flux; Net radiation; Soil temperature; Aerodynamic roughness; Surface resistance; Civil engineering and architecture; Samhällsbyggnadsteknik och arkitektur;

    Sammanfattning : The energy exchange in the soil-snow-vegetation-atmospheresystem was studied to improve the quantitative knowledge of thegoverning processes. The lack of such knowledge contributes tothe uncertainty in the applicability of many existing modelsindependent of the temporal or spatial scale. LÄS MER

  4. 3. Wind-wave interaction effects on offshore wind energy

    Författare :Ali Al Sam; Strömningsteknik; []
    Nyckelord :wind-wave; swell; atmospheric boundary layer; marine atmospheric boundary layer; atmospheric turbulence; Large-eddy simulation; actuator line; wind sea; offshore technology; wind energy; wind turbine; aerodynamic;

    Sammanfattning : This thesis is devoted to the investigation of the impacts of fast moving ocean surface waves on the aerodynamics of offshore wind turbines. The impacts of non-locally generated waves (swell) on the Marine Atmospheric BoundaryLayer (MABL) and thereby on offshore wind turbine aerodynamics are studied numerically by using Large Eddy Simulations and the Actuator Line Method. LÄS MER

  5. 4. Impact of Icing on Wind Turbines Aerodynamic

    Författare :Narges Tabatabaei; Michel Cervantes; Barakos George N.; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Strömningslära; Fluid Mechanics;

    Sammanfattning : Wind energy covered 11.6% of Europe electricity demand in 2017. Region with cold climates represent a strong potential for wind energy companies because of their sparse population and proper wind conditions. The global wind energy installations in cold climate regions is forecasted to reach a capacity of 186 GW by the end of 2020. LÄS MER

  7. 5. Mean Wind and Turbulence Conditions in the Boundary Layer above Forests

    Författare :Johan Arnqvist; Hans Bergström; Anna Rutgersson; Stefan Söderberg; Søren Larsen; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Wind power; Forest; Turbulence; Waves; Spectra; Wind model; Atmospheric stability; Vindkraft; Skog; Turbulens; Vågor; Spektra; Modell; Atmosfärisk stabilitet;

    Sammanfattning : As wind turbines have grown, new installation areas become possible. Placing wind turbines in forested landscapes introduce uncertainties to the wind resource estimation. LÄS MER