uDALES 1.0: a large-eddy simulation model for urban environments

Abstract

Urban environments are of increasing importance in climate and air quality research due to their central role in the population's health and well-being. Tools to model the local environmental conditions, urban morphology and interaction with the atmospheric boundary layer play an important role for sustainable urban planning and policy making. uDALES is a high-resolution, building-resolving, large-eddy simulation code for urban microclimate and air quality. uDALES solves a surface energy balance for each urban facet and models multi-reflection shortwave radiation, longwave radiation, heat storage and conductance, as well as turbulent latent and sensible heat fluxes. Vegetated surfaces and their effect on outdoor temperatures and energy demand can be studied. Furthermore, a scheme to simulate emissions and transport of passive and reactive gas species is present. The energy balance has been tested against idealised cases and the dispersion against wind tunnel experiments of the Dispersion of Air Pollution and its Penetration into the Local Environment (DAPPLE) field study, yielding satisfying results. uDALES can be used to study the effect of new buildings and other changes to the urban landscape on the local flow and microclimate and to gain fundamental insight into the effect of urban morphology on local climate, ventilation and dispersion. uDALES is available online under the GNU General Public License and remains under active maintenance and development.