Flow over Hills: A Large-Eddy Simulation of the Bolund Case

This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Springer and can be found at: link.springer.com/journal/10546.Simulation of local atmospheric flows around complex topography is important for\ud several applications in wind energy (short term wind forecasting and turbine siting and\ud control), local weather predictions in mountainous regions and avalanche risk\ud assessment. However atmospheric simulation around steep mountain topography\ud remains challenging and there exist several way to implement the topography in the\ud model. The Immersed Boundary Method provides an alternative approach that is\ud particularly well suited for efficient and numerically stable simulation of flows around\ud steep terrain. It uses a homogenous grid and permits a fast meshing of the topography.\ud In this article, the Immersed Boundary Method is used in conjunction with a Large Eddy\ud Simulation (LES) and tested against two unique data sets. In the first comparison, the\ud LES is used to reproduce the experimental results from a wind tunnel study of a\ud smooth three dimensional hill. In the second comparison, we simulate the wind field\ud around the Bolund Hill, Denmark, and make direct comparisons with field\ud measurements. Both cases show good agreement between the simulation results and\ud the experimental data, with the largest disagreement between simulation and\ud experiment observed near the surface. The source of error is investigated by\ud performing additional simulations with a different resolutions and surface roughness\ud properties