Large eddy simulation of turbine loading and performance in a wind farm

• We present an aeroelastic code coupled to an LES solver for wind farm modelling.
• Turbine control is included to allow transient above- and below-rated simulation.
• Turbine wakes, loads, power fluctuation and control utitlisation are examined.
• Wake meandering is observed and found to influence local onset wind directions.
• A simulation including yaw control is also presented with significant actuation.

We investigate multiple wind turbines operating in a small turbine array using a coupled LES/aero-elastic method. Wake interaction effects are assessed for multiple wind-speeds, with performance of the wind farm quantified, including measurement of efficiency, controller utilisation and loading effects. Power losses are shown to peak at over 40% for the full-wake case, with increased power fluctuation and control actuator usage noted at downwind turbine locations. Spectral analysis of the wake indicates a broad peak meandering frequency. Dynamic yaw control has also been included in the simulations – a first for LES simulation of wind farms – with significant yaw actuation observed due to local wind direction changes despite a constant global wind direction.