Simulating Flow and Hazardous Gas Dispersion by Using WRF–CFD Coupled Model under Different Atmospheric Stability Conditions

Abstract

In this paper, the Weather Research and Forecasting (WRF) model is coupled with the computational fluid dynamics (CFD) model to study the diffusion model of the accidental leakage of hazardous gas under different atmospheric stability conditions. First, the field test at Nanjing University was used to validate the different turbulence models of CFD. The experimental data confirm that the realizable k-ε model can describe the behavior of hazardous gas diffusion. On this basis, the diffusion process of the accidental release of tracer gas under different atmospheric stability conditions is simulated. The results show that atmospheric stability has a significant effect on the flow field distribution and the area of plume of hazardous substances. The ambient wind deflects under unstable conditions and vertical turbulence is slightly larger than that under neutral and stable conditions. Under stable conditions, the dilution of harmful gases is suppressed due to weak turbulent mixing. In addition, stable atmospheric conditions can increase near-surface gas concentrations.

Keywords

• WRF model
• CFD model
• dispersion
• atmospheric stability
• urban area