Cress
Help - Scour - Scour by jets - B28.9
Cress
Help - Scour - Scour by jets - B28.9
Hydraulic jump
In this part of the calculation rule the erosion process cause by descending and horizontal in-flowing
jets is handled. Some simple equations are presented that calculate the maximum erosion depth. The figures below show a number
of erosion situations associated with various hydraulic structures.
Usually a current/jet picks up particles from the bed/bottom and transports them
downstream of the impact area. The impact area is transformed into an energy dissipater, as a result of which an erosion
hollow is formed. the hydraulic jump
A hydraulic jump occurs when high flow velocities (with Fr > 1) enter an area with lower flow velocities, and there is a
transition from supercritical to sub critical flow. This phenomenon is characterised by a sudden rise of the water surface,
much turbulence and a big reduction in energy. The water depth behind a hydraulic jump can be calculated with the equation of
Bélanger:
equation 1