A quantitative analysis of visibility loss due to coupling impacts of spray clouds and rain

Poor visibility on wet pavements is a major cause of accidents. Vehicles travelling on wet pavements produce splash and spray that reduce visibility on roads. Besides, large rain particles in the air, which block and scatter the light, cause poor visibility for drivers. With the goal of quantifying the visibility loss caused by spray and rainfall. This work suggests using computational fluid dynamics (CFD) to evaluate the spray and rain effect on visibility. The volume-of-fluid (VOF) method was used to simulate spray dispersion generated by a simplified sport utility vehicle (SUV) in order to calculate spray concentration. Monte Carlo simulation was used to simulate the stochastic weakening process of light transmission in spray and rain. The visibility loss due to rain and splash was quantified. It can be concluded that the influence of rainfall is much less than the influence of splash.