要約

The characteristics of the velocity field of a free overfall (including the velocity profiles of and near the sliding jet, and in the pool) are investigated experimentally, using a novel flow visualization technique as well as fiber laser Doppler velocimetry (FLDV). The range of Froude number for the approaching flow upstream of a drop structure is from 0.75 to 1.32. Several detailed flow structures, regarding the mean horizontal velocity distributions and the circulating vortex flow inside the pool of a drop structure, are elucidated in the present study. An unique similarity profile of the mean horizontal velocity measured inside the pool is proposed both for supercritical and subcritical- approaching flow conditions.