Sökning: "wind turbine"

Visar resultat 21 - 25 av 194 avhandlingar innehållade orden wind turbine.

1. 21. Wind power wake modelling : Development and application of an actuator disc method for industrial utilization

   Författare :Nikolaos Simisiroglou; Stefan Ivanell; Thorsten Lutz; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Wind power; Offshore wind farm; Wakes; Actuator Disc Method ACD ; Computational Fluid Dynamics CFD ; Reynolds Average Navier–Stokes RANS ; WindSim; PHOENICS;

   Sammanfattning : As a wind turbine extracts energy from the wind it creates a region downstream where the wind velocity is decreased and the urbulence intensity is increased, this region is commonly called the wake region. Today’s wind farms include a large number of wind turbines position in tight layouts. LÄS MER

3. 22. Stability and transition on wind turbine blades

   Författare :Thales Coelho Leite Fava; Ardeshir Hanifi; Dan Henningson; Stefania Cherubini; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Boundary layer stability; free-stream turbulence; laminar-turbulent transition; low-frequency oscillations; rotation effects; wind turbine blades.; Gränsskiktsstabilitet; friströmsturbulens; laminär-turbulent omslag; lågfrekventa svängningar; rotationseffekter; vindkraftverksblad.; Teknisk mekanik; Engineering Mechanics;

   Sammanfattning : Transition on wind turbine blades is a highly complex phenomenon due to the myriad effects influencing the process. This thesis studies some of them, namely free-stream turbulence (FST), rotation, and three-dimensionality. The investigations employ large eddy simulations (LES) with and without (implicit or wall-resolved LES) a subgrid-scale model. LÄS MER

4. 23. Dynamic Models of Wind Turbines

   Författare :Abram Perdana; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; frequency stability; variable-speed; modeling; power system stability; validation; aggregated model; fixed-speed; voltage stability; wind turbine;

   Sammanfattning : The impact of wind power generation in the power system is no longer negligible. Therefore, there is an urgent need for wind turbine models that are capable of accurately simulating the interaction between wind turbines or wind farms and the power system. LÄS MER

5. 24. Characterization and forecasting of wind conditions over the Baltic Sea

   Författare :Christoffer Hallgren; Erik Sahlée; Julie Lundquist; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Baltic Sea; forecasting; low-level jet; lidar; machine learning; mesoscale meteorology; numerical weather prediction; post-processing; reanalysis; sea breeze; turbulence; wind atlas; wind energy; wind power; Meteorologi; Meteorology;

   Sammanfattning : To meet the increasing demand of sustainably produced electricity, the total number of installed wind turbines is rapidly increasing globally. Although onshore installations are dominating, offshore wind power is taking a greater share of the market every year. LÄS MER

7. 25. Wind-turbine harmonic emissions and propagation through a wind farm

   Författare :Kai Yang; Åke Larsson; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Renewable energy; Electric power system; Wind power; Power quality; Power system harmonics; Electric Power Engineering; Elkraftteknik; Energy Engineering; Energiteknik;

   Sammanfattning : The increasing demand for sustainable energy is one of the driving forces behind the increasing use of wind power by means of wind-turbines in electric power systems. Modern wind turbines commonly employ variable-speed-generator technology associated with a power-electronic converter as part of the grid connection. LÄS MER