Abstract: Physical and numerical models are often used to estimate the affecting area and intensity of atomization in to bebuilt projects. A mathematical model of atomization with high waterhead and big discharge was established for Qipei Project. The area affected by atomization and the rainfall intensity were simulated under several running cases of flood discharge of Qipei Project. Results suggest that heavy rainfall caused by atomization is mainly in the downstream plunge pool; the powerplant and its tailwater channel are outside the heavy rainfall area (rainfall intensity S≥10 mm/h); the left assembly bay and the left side of the tailwater channel are in the drizzle area(10 mm/h>S≥0.5 mm/h); whereas the powerplant and the side slope of the tailwater channel are slightly affected by the atomization.

Key words: flip trajectory, atomization caused by flood discharge；mathematical model；prediction