Channel Studio has the ability to compute supercritical flow profiles with hydraulic jumps automatically. During friction loss calculations, if the energy equation cannot balance, the software reverses the calculation procedure, i.e. from upstream to downstream, and computes the supercritical profile.
Hydraulic Jump
The Momentum Principle is used for determining depths and locations of hydraulic jumps. At each step (one tenth of the culvert length) during supercritical flow calculations, Culvert Studio computes the momentum and compares it to the momentum developed during the subcritical profile calculations.
During these calculations, Channel Studio computes the momentum M1, and compares it to the momentum developed during the subcritical profile calculations, M2. If M1 > = M2, it is established that a hydraulic jump must occur between these two cross-sections.
Momentum, M1, of the subcritical profile is greater than or equal to the momentum, M2, of the supercritical profile.
Where:
Q = Flow rate
A = Cross-sectional area of flow
Y = Distance from the water surface to the centroid of A
The location of the jump is somewhere along the culvert barrel when M1 = M2.
The length of the jump however is difficult to determine. There have been many experimental investigations which have yielded results which are contradictory. Many have generalized that the jump length is somewhere between 4 and 6 times the Sequent depth. Channel Studio assumes 5.