Large wind-farm aerodynamics

Background

Wind farms are cluster of wind turbines designed to extract energy from an incoming wind. If the turbines are isolated and far from each other, they work independently and the farm will produce the most. However, it is generally desired to keep as low as possible the size of a wind farm, limiting the available area: this helps reducing the cost of the grid between the turbines, for instance. Thereby, interactions between the wakes downstream of the various turbines are possible and they strongly affect the energy transfer between the free stream above the power plant (where much of the kinetic energy is present) and the farm (where the turbines are located to extract power from the wind). Maximizing the energy transfer between these two layers is the key to increase the energy yield of a farm.

Aims

This project aims at the detailed characterization of the flow over long wind farms, where more than 150 turbines are involved, in order to determine the aerodynamics properties of the wind, its turbulence features and how these are affected by the farm layout.

Approaches

An experimental campaign has been performed at the Minimum Turbulence Level (MTL) wind tunnel at KTH in 2018. Velocity measurements were performed by means of hot-wire anemometry, providing access to both mean and instantaneous velocity components, quantities of fundamental interest to characterize the momentum transfer taking place over the wind farm.

Keywords

Wind farms experiment

Project leaders

Antonio Segalini, KTH Royal Institute of Technology, FLOW

Other funding agencies

Vetenskapsrådet