Wind Farm Layout Optimisation

Abstract

This report investigates various methods of modelling the flow behaviour in the wake of a turbine. It is inclusive of the two dimensional, top-down views that are formed by Park, Prandtl and Eddy viscosity analytical models. Three dimensional finite element numerical models of the flow in the wake of a turbine were constructed using both laminar flow and the k - e turbulence closure. The impact of these models on a mixed integer linear programme that produces optimal wind farm layouts based on expected power harvest is explored. The effectiveness of the most common wake model, the Park model, is then analysed by comparing wind farm layouts and expected power harvests of the analytical models. It was found that the optimal layout patterns were different for each wake model. However, each wake model was used on the optimal layouts produced by the other wake models, and the drop in the expected power harvest was small. The Eddy viscosity model was the most different and the reasons behind this were investigated. The finite element models produced flow profile close to the Park and Prandtl models and hence it was not necessary to implement these into the optimisation programme. The finite element models were useful in verifying the analytical models and providing estimates of wake deficits required in Prandtl and Eddy viscosity model calculations. It was concluded that the simple Park model is the most efficient model to use when performing wind farm layout optimisation.