Development of LOcal-scale High-resolution atmospheric DIspersion Model using Large-Eddy Simulation. Part 5. Detailed simulation of turbulent flows and plume dispersion in an actual urban area under real meteorological conditions

We have developed a LOcal-scale High-resolution atmospheric DIspersion Model using Large-Eddy Simulation (LOHDIM-LES) to assess the safety at nuclear facilities and to respond to emergency situations resulting from accidental or deliberate releases of radioactive materials (e.g., a terrorist attack in an urban area). In parts 1–4, LESs of turbulent flows and plume dispersion over a flat terrain, around an isolated building, within building arrays with different obstacle densities, and within an actual urban area were performed, which showed the basic performance comparable to wind tunnel experimental technique. In this study, we extend the LOHDIM-LES to turbulent flows and plume dispersion in an actual urban area under real meteorological conditions by coupling with a meso-scale meteorological simulation model. The LES results of wind speed, wind direction, and concentration values are generally reproduced well. It is concluded that our coupling approach between LES and meso-scale meteorological models is effective in detailed simulations of turbulent flows and plume dispersion in urban areas under real meteorological conditions. (author)