Experimental–analytical investigation of super- to subcritical flow transition without a hydraulic jump

An experimental–analytical investigation was performed to explore whether a hydraulic jump in a transition from super- to subcritical flow regime can be avoided. As the free-surface profile passes the critical depth, the transitional point is a singular point. A transition structure was designed based on the energy principle and the singular point theory to gradually increase the flow depth, thereby eliminating the hydraulic jump. This profile was designed for approach flow Froude numbers between 1.5 and 7. To validate the analytical model, a comprehensive experimental study was conducted. Six hydraulic models of transition structures were experimentally investigated on the basis of the theoretical approach. The analytical results agreed well with the experimental results and those of former investigations. Observations indicated that the hydraulic jump is absent for a certain range of the Froude numbers.