Experimental study on energy dissipation and tailwater wave in two-stage stilling basin with supercritical inflow of low Froude number

This study investigates the geometric parameters of a two-stage stilling basin; 14 sets of tests were carried out in a horizontal flume with a supercritical inflow of relatively low Froude number (Fr₁ = 1.1 ∼ 1.85). The flow pattern, relative amplitude of the tailwater, and energy dissipation ratio were investigated. The two-stage stilling basin led to a hydraulic jump at each stage. Compared to the corresponding classical jump, the energy dissipation ratio in the two-stage stilling basin could be increased by 30%–45%. Herein, a novel method is proposed to calculate the energy dissipation ratio and relative amplitude of the tailwater. The investigation demonstrates the potential of two-stage stilling basin with low-Froude-number flow.