We present here a computational fluid dynamics (CFD) simulation of Lillgrundoffshore wind farm, which is located in the Oresund Strait between Sweden andDenmark. The simulation combines a dynamic representation of wind turbinesembedded within a Large-Eddy Simulation CFD solver, and uses hr-adaptivemeshing to increase or decrease mesh resolution where required. This allows theresolution of both large scale flow structures around the wind farm, and localflow conditions at individual turbines; consequently, the response of eachturbine to local conditions can be modelled, as well as the resulting evolutionof the turbine wakes. This paper provides a detailed description of the turbinemodel which simulates interactions between the wind, turbine rotors, andturbine generators by calculating the forces on the rotor, the body forces onthe air, and instantaneous power output. This model was used to investigate aselection of key wind speeds and directions, investigating cases where a row ofturbines would be aligned with the wind or at specific angles to the wind.Results shown include presentations of the spin-up of turbines, the observationof eddies moving through the turbine array, meandering turbine wakes, and anextensive wind farm wake several kilometres in length. The key measurementavailable for cross-validation with operational wind farm data is the poweroutput from the individual turbines, where the effect of unsteady turbine wakeson the performance of downstream turbines was a point of interest. The resultsfrom simulations were compared to performance measurements from the real windfarm to provide a firm quantitative validation of this methodology. Havingachieved good agreement between the model and actual wind farm measurements,the potential of the methodology to provide a tool for further investigationsof engineering and atmospheric science problems is outlined.
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