Wind energy research: Simulation of Wind Farm Aerodynamics

Objectives

Create a tool for the design of turbines in a wind farm and for development of wake control algorithms. This tool is based on turbine-response calculations with time-related modelling of wake interaction.

Project summary

Most wind energy is generated by turbines in a wind farm. Currently design requirements for wind turbines (IEC, GL and DNV) are basically formulated for wind loading on stand-alone turbines. Following IEC 61400-3 the effect of wake operation for wind turbines can be modelled with an engineering approach for increased turbulence.

Recently more detailed models have come under development for unsteady wind farm wake effects, including the 'meandering' motion. These models are named Dynamic Wake Meandering (DWM) models. Research and development have started for wind turbine controllers that aim to reduce the consequences of wake effects on turbines in a wind farm. DWM models and wake control algorithms cannot yet be included in an integral way in the conventional process of design load calculations as required for certification.

With the farm wake simulation tool developed in this project the aeroelastic response of the individual wind turbine is calculated in the same way as is common practice for wind turbine certification. This means that it still conforms to the latest IEC 61400-1 ed.3 and IEC 61400-3 ed.1 design requirements. In contrast to similar developments, the aerodynamic interaction in terms of transportation and deformation of the wake through a wind farm is modelled including time-dependent variations of the wake strength and side momentum.

The transportation of the wake is modelled using an engineering DWM model that describes the wind deficit in the wake of another turbine, added turbulence, and wake meandering. This implementation allows for various algorithms for wake development. On this basis an add-on is created for the ECN program FarmFlow which will be used for benchmarking.

Expected results

  • A version of the existing FOCUS6 integrated design package for 'Farm Wake Wind Turbine Simulation'. This version of FOCUS6 is flexible for implementation and application of different models for the meandering of the wind turbine wakes as well as for the transportation velocity of wind structures in wind direction.
  • Additional insight in the transportation of wind structures in wind direction and also in transverse direction, so-called meandering. In the FOCUS6 module for wind farms the basic default algorithm for wake meandering will be the 'Dynamic Wake Meandering' method as proposed for the upcoming IEC 61400-1 design.

Organisation

Project partners: WMC, ECN
Consulting partner: XEMC Darwind
Period: January 2015 - December 2015
Project partially funded by: FLOW (project P201406-003-WMC)
Project coordinator: Koert Lindenburg (WMC)

Contact

For inquiries please contact:

Knowledge Centre WMC
Kluisgat 5
1771 MV Wieringerwerf
the Netherlands
phone +31(0)227-50 49 49
info@wmc.eu