Impinging pressure and flood discharge atomization in high arch dams with flaring gate piers

This study discusses the effects of geometrical parameters of flaring gate piers, such as contraction ratio, sidewall extension ratio and plunge angle, on the impinging pressure and flood atomization based on hydraulic model tests and atomization simulations. It is found that the impinging pressure decreases and the length of rainstorm increases with the increasing impact collision of aerated jets. Decreasing the plunge angle and increasing the extension length of sidewall for violent collision should be considered in the design stage and protection measures for rainstorms should be taken into account. Reducing the atomization hazard by collision avoidance could be selected in the operational phase on the premise of safety factor of plunge pool. A simplified formula is developed to predict the length of rainstorm as a function of the maximum impinging pressure, for use as a reference in the design and modification of similar projects.