Risk Assessment of Urban Viral Pollutants Under Natural Wind Based on Fluent

Risk assessment is an important method to eliminate safety hazards and effectively realize accident prevention. In this paper, the power spectrum of natural wind and the time history curve of wind speed field were fitted by using FFT improved harmonic synthesis method. Based on Fluent software, k-e model was used for simulation. The study found that the maximum concentration in the contaminated area was consistent with the virus growth curve. At z = 3/5H, the width of the polluted area was narrow due to the change of natural wind. At z = 4/3H, the scope of the contaminated area at a gradually expands, posing a great threat to buildings A and B. The vortex in the flow field has great influence on the spread and diffusion of the virus. The center of the vortex has the highest concentration of virus, which can lead to dangerous secondary infections. Two concentration criteria could be used to find the most dangerous location in the complex and the maximum time people can stay. Traditional risk assessment is mainly based on experimental results and probability evaluation. This paper takes the numerical simulation results as the object of risk assessment, and opens up a new idea of risk assessment. Through the assessment of the possibility and consequence of the hazard, reasonable plans or measures to reduce the risk can be proposed.