High-resolution CFD modelling of Lillgrund Wind farm

A.C.W Creech,W.-G Früh,E Maguire

doi:10.24084/repqj11.504

Abstract

We report on a fully dynamic simulation of Vattenfall's Lillgrund offshore Wind Farm, with a focus on the wake effects of turbines on the performance of individual turbines, and of the farm as a whole.

Highlights

Due to the rapid increase in the development of substantial offshore wind farms, estimating the wind farm electricity production reliably has become ever more important
We will first present typical flow fields obtained in the simulations, and compare the power output from the simulations with comparable observations from the SCADA data of the wind farm
The high-resolution large eddy simulation (LES) computational model of the Lillgrund wind farm coupled with dynamic modelling of the turbine’s interaction with the wind and the resulting power output has successfully reproduced the main observed features gathered from SCADA data of that wind farm over a period of over two years

Summary

Introduction

Due to the rapid increase in the development of substantial offshore wind farms, estimating the wind farm electricity production reliably has become ever more important. Recent research has combined simple turbine models with flow models, with turbines often represented as simple porous discs [2], actuator discs [3], actuator lines [4], or lifting line representations [5] These can be embedded in RANS fluids solvers [6] or fixed-mesh LES codes [4][7] or an LES finite element solver with an unstructured, hr-adaptive mesh [8]. To allow fluid flow at both, turbine and farm scale to be resolved, the turbines are represented as cylindrical volumes, in which rotor lift and drag forces are based upon blade element momentum theory. The model used here has already been validated against wake measurements of a single turbine [3], and this work represents the extension and application of that model to the fully operational Lillgrund wind farm, situated in the sea between Denmark and Sweden [11], consisting of forty-eight 2.3 MW Siemens turbines

Model configuration

Velocity Fields

Power deficit

Discussion and Conclusions