Modeling of multi-rotor wind farms

Master thesis (2023)

Authors

Y.X.F. Birnie-Scott Aerospace Engineering

Contributors

D.J.N. Allaerts Wind Energy - Aerospace Engineering (mentor)
Maarten Paul van der Laan Technical University of Denmark (mentor)
Mads Christian Baungaard Technical University of Denmark (graduation committee member)
Mikkel Kiilerich Østerlund Vestas Wind System A/S (coach)
Faculty
Aerospace Engineering, Aerospace Engineering
Copyright: © 2023 Yann Birnie-Scott
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Published Date

01-08-2023

Language

English

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Faculty

Aerospace Engineering

Abstract

The recurred idea of developing multi-rotor wind turbines has led to the need of more accurate surrogate wake models which allow for a fast annual energy production (AEP) calculation and further understanding of the aerodynamic power losses of multi-rotor wind turbines.

The present thesis develops a surrogate wake model of a multi-rotor-two turbine validated against computational fluid dynamics (CFD) simulations of type RANS-AD. The outcome is a superposition model of an analytical representation of the wake which base function coefficients are stored in look-up tables as a function of the wind inflow conditions affecting the turbine. The derived surrogate model is able to predict the overall wind farm efficiency with more than 90% accuracy while compared to RANS-AD models.

Towards the end of the thesis, a comparison between a single-rotor wind farm of 18 V29 turbines and a multi-rotor wind farm composed by nine 2R-V29 turbines (hypothetical turbine) is evaluated through RANS-AD simulations within the same wind-farm area. The energy ouput showed to be highly dependent on the wind-farm geometry, and the wind direction average suggest that 5% more energy yield is obtained from the multi-rotor-farm for velocities below rated speed.