Vindkraft i skog med gläntor
Title: Vindkraft i skog med gläntor
SNIC Project: SNIC 2020/5-629
Project Type: SNIC Medium Compute
Principal Investigator: Alf-Erik Almstedt <>
Affiliation: Chalmers tekniska högskola
Duration: 2021-01-01 – 2021-10-01
Classification: 20301


The IEC criteria are used to design wind turbines, but in Sweden large areas is covered by forest which has been proven by Nebenfuhr and Davidson to increase the turbulence levels above the IEC design criteria [1]. Clearings located in the forest has been shown by Matsfelt to change the flow field [2]. In this work the loads on a wind turbine obtained by Large Eddy Simulations(LES) will be compared to SCADA data of a site in Sweden. Different nacelle angles will be evaluated, the west represents a clearing and the south represents forest. The fatigue loads from the LES for the two nacelle angles with and without complex terrain will be computed. This is done by implementing the exact forest height at the test site in STAR-CCM+. The method developed by Shaw and Schumann will be used to simulate the forest, this by adding a drag source to the transport equation of momentum [3]. The loads on the NREL 5MW Reference wind turbine used in the simulations will be evaluated using a one way coupling to the aeroelastic solver FAST developed by NREL [4, 5]. In the second part of this SNIC project, the size and location of the clearing will be optimized. References [1] Bastian Nebenfuhr and Lars Davidson, 2014, “Influence of a forest canopy on the neutral atmospheric boundary layer a LES study”, ETMM10: International ERCOFTAC Symposium on Turbulence Modelling and Measurements, Marbella, Spain. [2] Johanna Matsfelt, 2018, “Large Eddy Simulation of clearings in forest and their effect on wind turbine”, Lic. Thesis, Chalmers university of technology. [3] Roger Shaw and Ulrich Schumann, 1992, “Large-eddy simulation of turbulent flow above and within a forest”, Boundary-Layer Meteorology, vol. 61, pp. 47-64. [4] Jason Jonkman and Marshall Buhl, 2005, “FAST user’s guide”, Technical Report NREL/EL-500-29798, National Renewable Energy Laboratory, Golden, Colorado. [5] Jason Jonkman and Sandy Butterfield and Walter Musial and George Scott, 2009, “Definition of a 5-MW reference wind turbine for offshore system development”, Technical Report NREL/TP-500-38060, National Renewable Energy Laboratory, Golden, Colorado. [6] ASTM, 1985, “Standard practices for cycle counting in fatigue analysis”, Technical report, American Society for Testing and Materials.