Das Projekt "Development of a Large-Eddy Simulation framework for wind energy studies" wird vom Umweltbundesamt gefördert und von Ecole Polytechnique Federale de Lausanne, Institut de Thermique, Laboratoire d'Energetique Industrielle durchgeführt. Accurate prediction of wind, turbulence and their interactions with wind turbines and wind farms is of great importance for the optimal design (turbine siting) of wind energy projects. It can also provide valuable quantitative insight into the effects of wind farms on the local meteorology. Computational fluid dynamics has the potential to provide the wealth of data required to understand the dynamics of the highly turbulent atmospheric flow at all the scales of interest to wind energy studies (ranging from kilometers down to meters). The accuracy of computer models, however, hinges on our ability to parameterize the dynamics of the flow that cannot be explicitly resolved in the simulations, because they occur at scales smaller than the grid scale. A novel computational framework is proposed here to simulate the interaction between the turbulent wind and wind turbines. The new computer models will be carefully validated using data collected in a wind tunnel and in the field inside a large wind farm. We will use miniature wind turbines (single turbines and multiple turbines in different wind-farm configurations) placed in a wind tunnel to isolate and study the effects on the flow of different atmospheric conditions (as affected by land-surface characteristics such as roughness and temperature) and wind turbine characteristics and arrangements (separation between turbines, alignment, etc.). In the field experiments, vertical and horizontal transects of the mean wind velocity and turbulence will be measured using sonic anemometers and lidars. Both wind-tunnel and field measurements will be used to validate the computational framework and guide the development of improved models. Finally, after the computational framework has been carefully validated, numerical experiments will be carried out to study the interaction between atmospheric flow and wind farms under different thermal conditions typical of nighttime and characterized by high shear and strong wind at relatively low altitudes. This situation is of particular interest due to its high wind-energy potential, but also because of the well-known difficulties associated with its prediction. Emphasis will be placed on understanding the effects of wind farms on the local meteorology through their impact on the wind velocity and temperature distributions as well as the exchange rates of heat between the land surface and the atmosphere.