Analyze rectangular channel jumps with practical engineering inputs. Get sequent depth, losses, ratios, and checks. Download results, inspect graphs, and compare worked example values.
| Case | y1 (m) | q (m²/s) | b (m) | Q (m³/s) | V1 (m/s) | F1 | y2 (m) | Head loss (m) |
|---|---|---|---|---|---|---|---|---|
| Worked Example | 0.30 | 1.20 | 1.50 | 1.80 | 4.00 | 2.33 | 0.85 | 0.16 |
| Moderate Jump | 0.25 | 1.00 | 2.00 | 2.00 | 4.00 | 2.56 | 0.79 | 0.19 |
| Strong Jump | 0.20 | 1.40 | 2.20 | 3.08 | 7.00 | 5.00 | 1.32 | 1.05 |
These values illustrate how greater approach velocity and Froude number usually increase sequent depth and energy dissipation.
This page uses the classical rectangular channel hydraulic jump relations.
Approach Froude number: F1 = V1 / √(g × y1)
Sequent depth: y2 / y1 = 0.5 × [√(1 + 8F1²) − 1]
Specific energy: E = y + V² / (2g)
Head loss: ΔE = E1 − E2
Closed form loss: ΔE = (y2 − y1)³ / (4y1y2)
Unit discharge relation: q = Q / b = V × y
The equations assume a horizontal rectangular channel, hydrostatic pressure distribution away from the roller, and negligible sidewall effects.
Hydraulic jumps are used in stilling basins to dissipate excess kinetic energy and protect downstream beds, aprons, and structures from erosion.
The most sensitive inputs are the approach depth and discharge. Small changes in these values can alter the Froude number and produce a noticeable change in sequent depth.
If the approach Froude number is near one, a stable jump may not form. That condition often requires reassessment of the flow regime and geometry.
This calculator provides fast design guidance. Final work should also consider tailwater control, basin geometry, roughness, air entrainment, and site-specific standards.
Head loss is the specific energy dissipated when supercritical flow changes to subcritical flow through the jump.
It rejects values when depth, gravity, discharge, width, or velocity are invalid, or when the approach Froude number is not greater than one.
The jump converts kinetic energy into turbulence and raises water depth while slowing the flow downstream.
No. The displayed equations are the standard rectangular channel relations. Other sections need different momentum and geometry treatments.
Designers often use a factor around 5 to 7 times the jump height for quick estimates, then refine with project criteria.
One comes from specific energy difference. The other uses the closed-form depth relation. They should closely match.
It is a simple Froude-based classification that labels the jump as undular, weak, oscillating, steady, or strong.
Yes. The page includes CSV export for tabular data and PDF export for a quick report snapshot.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.