Numerical Modeling of Wind Turbine Wakes

TLDR

The study presents an aerodynamical model for three‑dimensional flow fields around wind turbine rotors, aimed at analyzing and verifying the assumptions of simple engineering models. The algorithm couples a 3‑D Navier‑Stokes solver with an actuator‑line technique, iteratively determining blade loading via a blade‑element approach and tabulated airfoil data, and is applied to a 500 kW Nordtank turbine with three LM19.1 blades. Computed power production agrees well with measurements, and the simulations provide detailed insights into wake features such as interference factor distributions and vortex structures.

Abstract

An aerodynamical model for studying three-dimensional flow fields about wind turbine rotors is presented. The developed algorithm combines a three-dimensional Navier-Stokes solver with a so-called actuator line technique in which the loading is distributed along lines representing the blade forces. The loading is determined iteratively using a blade-element approach and tabulated airfoil data. Computations are carried out for a 500 kW Nordtank wind turbine equipped with three LM19.1 blades. The computed power production is found to be in good agreement with measurements. The computations give detailed information about basic features of wind turbine wakes, including distributions of interference factors and vortex structures. The model serves in particular to analyze and verify the validity of the basic assumptions employed in the simple engineering models.