Hydraulic Jump Calculator

Complete Guide to Hydraulic Jump

The Hydraulic Jump Calculator determines sequent depths, energy loss, and jump efficiency in open channels. Essential for stilling basins and spillways. Pair with Channel Flow and Hydraulic Gradient tools.

Jump Formation

Occurs when supercritical flow (Fr > 1) transitions to subcritical (Fr < 1).

Sequent Depth (Rectangular)

\[ y_2 = \frac{y_1}{2} \left( -1 + \sqrt{1 + 8 Fr_1^2} \right) \]

Fr₁ = v₁ / √(g y₁)

Energy Loss

\[ \Delta E = \frac{(y_2 - y_1)^3}{4 y_1 y_2} \]

Jump Length

L_j ≈ 6 (y₂ - y₁) for strong jumps

Step-by-Step

  1. Compute v₁ = Q / A₁
  2. Fr₁ = v₁ / √(g y₁)
  3. Solve for y₂
  4. ΔE, L_j, efficiency

Example: Rectangular

Q=10 m³/s, y₁=0.5 m, b=5 m:

  • Fr₁ = 5.68
  • y₂ = 3.15 m
  • ΔE = 2.1 m
  • L_j ≈ 15.9 m

Jump Types

Fr₁Type
1–1.7Undular
1.7–4.5Weak
4.5–9Oscillating
>9Strong

Best Practices

  • Use baffles for weak jumps
  • Ensure tailwater control
  • Check air entrainment

Common Mistakes

  • Ignoring non-rectangular sections
  • Wrong Fr calculation
  • Forgetting energy loss

Advanced Topics

  • Submerged jumps
  • USBR stilling basins
  • CFD modeling

Conclusion

Accurate hydraulic jump design prevents erosion and ensures energy dissipation. Our calculator delivers instant, code-compliant results for safe channel transitions!

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