Jordan Journal of Civil Engineering

Comparative Analysis of the Positive and Negative Steps in a Forced Hydraulic Jump


S. Bakhti; A. Hazzab;


In the field of hydraulic constructions, restoring water within a stream is a very common issue. To avoid important and non-controlled modifications in streams, energy dissipation is often essential to convert a flow with high mechanical energy into a flow with low mechanical energy. In the works of dissipation, a regime change of the flow intervenes: at the entry of these works, it is torrential, at the exit it is fluvial, and this transition causes a hydraulic jump. The damping basin is the central element of the energy dissipation. The step (or steps (positive or negative)), represents the particular device related to such a work to support the formation of the jump in the basin, which makes the dissipater more compact, to improve the stability of the process and to increase the capacity of dissipation. In the intention not to move away from the physical reality of the phenomenon of the jump, this work is based on an experimental research. The attention is mainly related to the jump forced by a positive and a negative step. The comparisons between the two types of steps concerning stability, effectiveness and compactness were conducted and analyzed through experimental measurements.


Damping basin, Forced jump, Positive step, Negative step.