An abrupt rise in water level when flow changes from supercritical to subcritical.
When supercritical flow slows abruptly to subcritical, the depth jumps with significant energy dissipation: y₂/y₁=½(√(1+8Fr₁²)-1). Used in stilling basins to dissipate energy below dams and spillways, preventing erosion.
Water leaving a spillway forms a jump in the stilling basin.
A hydraulic jump dissipates energy and changes flow state, which is used in spillways and stilling basins to protect structures.
An abrupt rise in water level when flow changes from supercritical to subcritical.
A hydraulic jump dissipates energy and changes flow state, which is used in spillways and stilling basins to protect structures.
A sudden rise in water depth as fast shallow flow changes to slow deep flow, dissipating a large amount of energy.
It dissipates the high energy of spillway flow so that it does not scour the river bed downstream.
Typical applications include designing a stilling basin below a dam spillway, predicting the water level change after a sluice gate and checking energy loss in a channel with a sudden change in slope.
Study "Open channel flow" first (topic 74 of 105 in Thermodynamics & Fluids). It covers the groundwork this topic builds on.
Conjugate depths. Energy loss ΔE=(y₂-y₁)³/(4y₁y₂). Fr₁ >1.7 for jump.
Water leaving a spillway forms a jump in the stilling basin.
The next topic is "Compressible flow", which builds directly on this one.
It is classed as Advanced in Thermodynamics & Fluids (topic 75 of 105). It is an advanced topic. It assumes you are comfortable with the intermediate topics in Thermodynamics & Fluids.
Want to practise? Open the interactive course for quick checks, quizzes, simulations and progress tracking.