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Hydraulics2D

Open Channel Flow: Non-Uniform Flow - Theory & Concepts - Specific Energy

Specific energy, critical controls, momentum function, hydraulic jumps, gradually varied flow equations and profiles, and direct- and standard-step computations.

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Specific Energy and Alternate Depths

Rectangular channel with a numerically bracketed alternate-depth solution.

Unit discharge
5.000 m²/s
Critical depth
1.3659 m
Minimum energy
2.0489 m
Selected energy
2.0663 m
Selected regime
Subcritical (Fr=0.869)
Alternate depth
1.24734 m
Alternate regime
Supercritical (Fr=1.146)
Energy residual
-9.69e-11 m
depth y (log scale)energy E (log scale)criticalselectedalternate

For any energy above the minimum, the shallow and deep roots lie on opposite sides of critical depth. The logarithmic axes keep both roots visible when their magnitudes differ greatly.