A1 Journal article (refereed), original research

Experimental and Numerical Modelling of Flow over Complex Terrain: The Bolund Hill


Publication Details
Authors: Conan Boris, Chaudhari Ashvinkumar, Aubrun Sandrine, van Beeck Jeroen, Hämäläinen Jari, Hellsten Antti
Publication year: 2015
Language: English
Related Journal or Series Information: Boundary-Layer Meteorology
JUFO-Level of this publication: 1
Open Access: Not an Open Access publication

Abstract
In the wind-energy sector, wind-power forecasting, turbine siting, and turbine-design selection are all highly dependent on a precise evaluation of atmospheric wind conditions. On-site measurements provide reliable data; however, in complex terrain and at the scale of a wind farm, local measurements may be insufficient for a detailed site description. On highly variable terrain, numerical models are commonly used but still constitute a challenge regarding simulation and interpretation. We propose a joint state-of-the-art study of two approaches to modelling atmospheric flow over the Bolund hill: a wind-tunnel test and a large-eddy simulation (LES). The approach has the particularity of describing both methods in parallel in order to highlight their similarities and differences. The work provides a first detailed comparison between field measurements, wind-tunnel experiments and numerical simulations. The systematic and quantitative approach used for the comparison contributes to a better understanding of the strengths and weaknesses of each model and, therefore, to their enhancement. Despite fundamental modelling differences, both techniques result in only a 5% difference in the mean wind speed and 15% in the turbulent kinetic energy (TKE). The joint comparison makes it possible to identify the most difficult features to model: the near-ground flow and the wake of the hill. When compared to field data, both models reach 11% error for the mean wind speed, which is close to the best performance reported in the literature. For the TKE, a great improvement is found using the LES model compared to previous studies (20% error). Wind-tunnel results are in the low range of error when compared to experiments reported previously (40% error). This comparison highlights the potential of such approaches and gives directions for the improvement of complex flow modelling.

Last updated on 2017-22-03 at 14:43