atmosphere Article Large Eddy Simulations of Turbulent and Buoyant Flows in Urban and Complex Terrain Areas Using the Aeolus Model Akshay A. Gowardhan *, Dana L. McGuffin , Donald D. Lucas , Stephanie J. Neuscamman, Otto Alvarez and Lee G. Glascoe Lawrence Livermore National Laboratory, Livermore, CA 94551, USA;
[email protected] (D.L.M.);
[email protected] (D.D.L.);
[email protected] (S.J.N.);
[email protected] (O.A.);
[email protected] (L.G.G.) * Correspondence:
[email protected] Abstract: Fast and accurate predictions of the flow and transport of materials in urban and complex terrain areas are challenging because of the heterogeneity of buildings and land features of different shapes and sizes connected by canyons and channels, which results in complex patterns of turbulence that can enhance material concentrations in certain regions. To address this challenge, we have developed an efficient three-dimensional computational fluid dynamics (CFD) code called Aeolus that is based on first principles for predicting transport and dispersion of materials in complex terrain and urban areas. The model can be run in a very efficient Reynolds average Navier–Stokes (RANS) mode or a detailed large eddy simulation (LES) mode. The RANS version of Aeolus was previously validated against field data for tracer gas and radiological dispersal releases. As a part of this work, we have validated the Aeolus model in LES mode against two different sets of data: (1) turbulence quantities measured in complex terrain at Askervein Hill; and (2) wind and tracer data from the Citation: Gowardhan, A.A.; Joint Urban 2003 field campaign for urban topography.