Abstract: The heavy rainfall and mist flow induced by flood discharge atomization of high dam projects have negative effect on the hydropower project and its surrounding environment. Previous researches were focused on the rainfall intensity distribution on the downstream banks, while the source area of the atomization is still not well revealed. Through generalized hydraulic model tests, the rainfall intensity in the atomization source in the progress of a deflecting flow nappe dropping in the downstream water were measured, under different hydraulic conditions. The horizontal distribution was analyzed, and the causes of atomization sources and rainfall intensity distribution in the upstream, downstream and side regions around the nappe drop point were determined. The variation of nappe drop position and rainfall intensity distribution along with the change of water flow and head difference were also preliminarily investigated.

Key words: flood discharge atomization, atomization source area, nappe drop area, rainfall intensity