The abrupt increase in depth of rapidly
flowing water is called hydraulic depth.Flow at the jump changes from a
supercritical to a subcritical stage with an accompanying loss of kinetic
energy. The change in depth occurs over a finite distance, known as the length
of jump. The upstream surface of the jump, known as the roller, is a turbulent
mass of water.
The depth before a jump is the initial depth, and the depth after a jump is the
sequent depth. The specific energy for the sequent depth is less than that for
the initial depth because of the energy dissipation within the jump.
F=[ d22- d12]w/2
where d1 =depth before
jump, ft (m)
d2 =depth after jump, ft
(m)
w=unit weight of water, lb/ft3
(kg/m3)
