Hydraulic jump

Common card · No. 434736

A hydraulic jump is an abrupt increase in the depth of a fast-moving liquid stream in an open channel, which is accompanied by a decrease in speed. The jump appears as a wavy or turbulent region between the high-speed upstream flow and the slower downstream flow. A common example is the circular jump formed when a tap runs into a kitchen sink. Hydraulic jumps occur below dam spillways and in rivers. Hydraulic jumps may be stationary, as below a dam, or they may propagate as surges along a stream, as in a tidal bore. Civil engineers design spillways and stilling basins to create hydraulic jumps that dissipate the mechanical energy of water flowing over dams. A hydraulic jump can form only when the upstream flow moves faster than shallow-water waves, so that small disturbances to the flow cannot travel upstream. For speeds only slightly above the wave speed, the transition is a rolling wave. As the flow speed increases, the transition becomes more abrupt, until at high enough speeds the front...

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