Distributions of Hydraulic Forces Acted on the Gate Bottom in Vibration

Abstract

The distributions of hydraulic pressure acted on the gate bottom in vibration were measured and the damping coefficients of hydrodynamic forces were analysed for three typesof gates. The study involves forced oscillation tests and it is concluded that the flat bottom has two kinds of modes of negative damping caused by vortex in the lower range of reduced volocity (Vr) and by separated stream line in the higher range of Vr. The beveled edge (α=+15°) has the negative damping only in the higher range of Vr and another one (α=-15°) has none. Hydraulic discussions for these results were given.