Numerical simulation of atomization rainfall and the generated flow on a slope

This article studies the atomization rainfall and the generated flow on a slope by numerical simulations. The atomization rainfall is simulated by a unified model for splash droplets and a suspended mist, and the distribution of the diameter of splash rain drops is analyzed. The slope runoff generated by the atomization rainfall is simulated by a depth-averaged 2-D model, and the localization of the rainfall intensity in space is specially considered. The simulation results show that: (1) the median rain size of the atomization rainfall increases in the longitudinal direction at first, then monotonously decreases, and the maximum value is taken at the longitudinal position not in consistent with the position where the maximum rain intensity is taken. In the lateral direction the median rain size monotonously decreases, (2) since the atomization rainfall is distributed in a strongly localized area, it takes a longer time for its runoff yield to reach a steady state than that in the natural rainfall, the variation ranges of the water depth and the velocity in the longitudinal and lateral directions are larger than those in the natural rainfall.