An improved numerical model of ski-jump flood discharge atomization

Atomizing rainfall caused by flood discharge of high dams poses a great threat to the safety of powerhouse and ecological environment. As an indispensable means, numerical calculation is widely used in the safety design of discharge structures. The distribution of rainfall intensity is closely related to the trajectory nappe shape, jet trajectory distances, the splashed water droplet diameter and its velocity, and the spatial distribution of downstream nappe wind. In this paper, an experimental result is used to verify the improved stochastic splash mathematical model under different bucket types and discharge conditions, and the sensitivity of downstream rainfall intensity distribution to the shape of trajectory nappe, discharge flow, spatial distribution of downstream nappe wind, and the corresponding relationship between the droplet diameter and its splashing velocity is analyzed. The results show that the calculation accuracy of downstream rainfall intensity distribution is significantly improved when the above factors are taken into consideration. It is found that the bucket type and flood discharge rate play the greatest role in the rainfall intensity distribution, followed by the downstream nappe wind distribution, and finally the corresponding relationship between the diameter and velocity of splash droplets. Therefore, these factors should be considered comprehensively when the rainfall intensity distribution of flood discharge atomization is calculated. This study can help us to understand the influence factors of flood discharge atomization more deeply and predict the distribution of flood discharge atomization rainfall intensity more accurately.