Abstract: To predict the characteristics of atomized jet nappes in high dam flood discharge caused by complicated aerial nappe collisions, this paper presents a numerical method for plane-facade nappe collision modes, considering the features of atomized sources and atomized rainfall fields, together with its engineering application at the Xulong hydropower station. The calculations show that the distributions of atomized sources and atomized rainfalls depend on the shape of flip buckets. For optimized bucket scheme II under the adverse wind condition, the area of atomized heavy rain is larger under the flood of 5000-year period than that of 100-year period. In the former case, the downstream boundary of the protection area is shifted downstream by 50 m up to pile number 0+895 m, and the highest protection elevation is raised by 9 m and 13 m on the left and right banks respectively, exceeding the dam crest by 69 m and 55 m respectively. Under the adverse wind and rain, the design flood protection standard requires a longitudinal range of 0+(-3 m) to 0+862 m with the bank protection elevations of 2382 m on the left and 2391 m on the right, and the check flood protection requires a longitudinal range of 0+(-9 m) to 0+938 m with the bank protection elevations of 2370 m on the left and 2371 m on the right.

Key words: water release structure hydraulics, flood discharge atomization, aerial atomized sources, atomized sources of plunge pool, splashing atomized rainfall, jet buckets design, prediction and control