Large-Eddy Simulation of the Oklahoma City Joint Urban 2003 Experiment Using Uintah:MPMICE

Local urban-scale climate processes are modulated by a wide range of factors including urban morphology, properties of urban surfaces, and vegetation. These factors contribute significantly to strong spatial variability observed in urban areas. Accurately modeling the impact of these elements requires detailed information about transport processes at small scales. At the same time, integrating the effects of individual urban elements to larger scales or evaluating citywide policy initiatives, requires the ability to model a wide range of length scales. Here, we use the Large-Eddy Simulation (LES) technique combined with Uintah:MPMICE's massively parallel fully-coupled fluid-structure interaction (FSI) solver to run a simulation that simultaneously captures the unsteady local processes and the large scale city-wide flow patterns in a realistic urban area. To accomplish this, we used detailed surface boundary conditions with resolved surface roughness elements and a new advanced inflow grid-turbulence generator. This provided realistic large-scale atmospheric forcing parameters and appropriate atmospheric conditions. Our new approach to modeling the atmospheric boundary layer (ABL) provides an unprecedented level of physical description, allowing us to accurately model momentum and dispersion in real cities. We will present results from IOP8 (intensive observation period 8) of the Joint Urban 2003 experiment in downtown Oklahoma City (OKC), which includes simultaneously resolving turbulence around individual buildings and capturing the full dynamic range of scales present in the ABL. Our findings indicate that the tool is capable of capturing complex flow structures and flow topology features around individual buildings and street canyons at small scales and modeling pollutant transport at city scales.