Avancerad sökning

Visar resultat 1 - 5 av 183 avhandlingar som matchar ovanstående sökkriterier.

1. 1. 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

3. 2. Fault Behavior of Wind Turbines

   Författare :Francesco Sulla; Industriell elektroteknik och automation; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Wind Turbines; Short-Circuit Currents; Doubly-Fed Induction Generator; Grid Fault Ride-Through; Voltage Support; Weak Grid;

   Sammanfattning : Synchronous generators have always been the dominant generation type in the grid. This fact affected both planning and operation of power systems. With the fast increase of wind power share in the grid in the last decade, the situation is changing. In some countries wind power represents already a consistent amount of the total generation. LÄS MER

4. 3. Human response to wind turbine noise : perception, annoyance and moderating factors

   Författare :Eja Pedersen; Sten Ljunggren; Högskolan i Halmstad; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; Noise; Environmental exposure; Wind; Audio-visual interaction; Low-level noise exposure; NATURAL SCIENCES; NATURVETENSKAP; wind turbines; noise annoyance; sound perception; audio-visual interaction; low-level noise exposure;

   Sammanfattning : Aims: The aims of this thesis were to describe and gain an understanding of how people who live in the vicinity of wind turbines are affected by wind turbine noise, and how individual, situational and visual factors, as well as sound properties, moderate the response.Methods: A cross-sectional study was carried out in a flat, mainly rural area in Sweden, with the objective to estimate the prevalence of noise annoyance and to examine the dose-response relationship between A-weighted sound pressure levels (SPLs) and perception of and annoyance with wind turbine noise. LÄS MER

5. 4. The Power Qualities of Wind Turbines

   Författare :Åke Larsson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; wind turbines; power quality; frequency variations; flicker; measurements;

   Sammanfattning : The power quality of wind turbines is dealt with in this dissertation. The thesis consists of four parts. The first part describes the electrical systems used in wind turbines. The second part presents the results of measurements of different types of wind turbines connected to different types of grids. LÄS MER

7. 5. Numerical Computations of Wakes Behind Wind Farms

   Författare :Ola Eriksson; Stefan Ivanell; Simon-Philippe Breton; Anna Rutgersson; Dan Henningson; Niels Troldborg; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Wind turbine; Wind power; Wind farm; Wakes; Long distance wakes; Farm-Farm; Farm to farm interaction; Wind farm cluster; Large Eddy simulations; LES; Actuator disc method; ACD; CFD; Ellipsys3D;

   Sammanfattning : More and larger wind farms are planned offshore. As the most suitable build sites are limited wind farms will be constructed near to each other in so called wind farm clusters. Behind the wind turbines in these farms there is a disrupted flow of air called a wake that is characterized by reduced wind speed and increased turbulence. LÄS MER