Abstract
By observing the movement of numerous surface foam on floods photographed by air crafts, the author has discovered that there commonly exist, along the longitudinal axis, parallel cycloidal flows, in which adjacent vortices have opposite directions of rotation. Measuring floats go down along the convergent flow. Also a radio-controlled air boat, which moves around upon the flood flow, acoustic survey system and an automatic dropping device of the floats has been developed. The positions of the floats were measured by LASER track total-station at the river side. The measurement cross section was chosen at a turning point of alternating bars. The accuracy of discharge measurement will be highly improved by studying the ratio of the surface convergent velocity to mean velocity of the parallel cycloidal flows.
