Quick Environmental Simulation: Benchmark with JU2003

Abstract: Fast dispersion model solvers are crucial tools for real-time prediction of the transport and dispersion of airborne materials in complex environments. These models are particularly important in urban areas where the flow encounters a complex built environment, and accurate prediction of pollutant dispersion is essential for public safety and environmental protection. The importance of these models lies in their ability to provide accurate predictions in a timely manner, which is critical in emergency situations involving hazardous releases. This work utilises Quick Environmental Simulation (QES), a GPU-accelerated, low-computational-cost solver, to compute mean flow, turbulence, and concentration fields in a complex urban environment. QES can provide faster-than-real-time predictions, an advantage compared to current traditional computational fluid dynamics methods such as Reynolds-averaged Navier-Stokes (RANS) and Large-eddy Simulation (LES) that are computationally more intensive. We present a brief introduction to QES, which consists of QES-Winds, a quasi-steady 3D wind flow model that uses mass conservation combined with low-order physics-based models to mimic momentum effects around obstacles; QES-Turb, an algebraic turbulence model; and QES-Plume, a Lagrangian dispersion model that predicts the transport of passive scalars. The capability of QES to simulate complex urban flows is tested by comparing the 3D dispersion results with the established Joint Urban (JU) 2003 field experiments conducted in Oklahoma City, US. Comparisons are also made with the Quick Urban and Industrial Complex (QUIC) Dispersion Modeling System, another low-cost dispersion software developed by Los Alamos National Laboratory (New Mexico, US). Keywords: 3D wind field, low-order model, fast dispersion model, urban flows