Abstract: In order to study the energy characteristics of water flow on stepped spillway, we conducted model test of stepped spillway with slope ratio of 1∶1.25 and different step heights. The results indicated that gross head of stepped spillway decreased dramatically along the flow path, and specific energy on stepped spillways first increased and then remained constant. The change of specific energy determines the gross head,and low stable specific energy reflects better energy dissipation. Two dimensionless parameters of stable specific energy and its influencing factors were obtained through dimensional analysis,and a good power function law was found between the two dimensionless parameters based on the data from test and related literature, with the correlation coefficient between 0.9949 and 0.9972. An empirical formula for calculating the residual energy and gross dissipation rate was put forward to provide references for related design.

Key words: stepped spillways, flow energy characteristics, specific energy of water flow, dimensional analysis, dissipation rate