Specific Energy & Critical Depth

Inside this lesson

Define specific energy E = y + V²/2g and write it as E = y + q²/(2gy²) for a rectangular channel
Sketch the specific-energy diagram and identify the subcritical branch, supercritical branch, and critical point
Compute the critical depth y_c = (q²/g)^(1/3) and the minimum specific energy E_min = (3/2)y_c
Explain the concept of alternate depths (same E, different branches)
Use the specific_energy simulator to explore the diagram and the critical state

Unlock the full Mechanical Engineering bundle

Every paid lesson across both the Fluid Mechanics and Solid Mechanics courses — one purchase, both courses.
Interactive simulators for the Moody chart, Bernoulli's equation, hydrostatic forces, and more.

Get the bundle →

One-time purchase — see options on the next page.

or unlock everything with all-access

Not ready yet? Keep learning for free — start with the hydrostatic equation or what a fluid is.

⚖️

Educational content covering topics typical of a first- and second-year mechanical engineering curriculum. Not a substitute for accredited coursework, and not suitable for real fluid-system design without review by a licensed professional engineer.