Abstract
The temporal evolution of the scour hole upstream of a dam gate under free surface overflow is experimentally investigated. A total of 18 experiments is conducted for different flow discharges, movable bed particles, and geometries of gates. The scour length, maximum scour depth, scour width, and scour volume are evaluated to clarify the temporal evolution of the scour hole topography. Experimental results show that a feature of temporal evolution of the scour hole topography has similarity between experimental conditions. Also, two types of dimensionless hydraulic parameter, i.e. the relative flow velocity and the ratio of discharge distribution, are found to have a positive correlation with the dimensionless scour volume. In addition, the influence of the ratio of discharge distribution on the dimensionless scour volume is found to vary with the elapsed time, whereas that of the relative flow velocity is constant in time.
