🌊 Gradually Varied Open Channel Flow (Standard Step)

Model gradually varied open channel flow profiles (M1, M2, M3, S1, S2, S3 backwater curves): critical depth (yc), normal depth (yn), Froude number, and reach distance by Standard Step Method.

⚡ Fortran 90 Engine Double Precision (IEEE 754) ✓ ISO / ASME Validated
📊 Solver Telemetry ● ACTIVE
👁️ Consultations 24
⚡ Calculs faits 21
💾 Téléchargements 125 📦 Code Fortran 4.5 KB
📅 Mise en service Jun 2026
⏱️ Latence < 1 ms
⚡ Outils & Rapports :
💾 Télécharger Fortran 90

🌊 Open Channel Longitudinal Profile & Water Surface Curve

Real-time visual simulation: Bed slope $S_0$, normal depth $y_n$, critical depth $y_c$, and backwater surface $y(x)$

📝 Configuration & Presets

🏞️ Dam M1 Backwater 📉 Drop M2 Drawdown 📐 Trapezoidal S1 Steep ⚡ Sluice Gate M3 Flow
📐 Channel Cross-Section Geometry
💧 Flow & Bed Slope Parameters
Known water level at weir, dam, gate or drop
Gradually Varied Flow Dynamic Equation:
• Governing ODE: dy / dx = (S₀ − Sf) / (1 − Fr²)
• Friction Slope: Sf = n² · V² / Rh4/3
• Specific Energy: E = y + V² / (2 g) [meters]
• Standard Step Reach Distance: Δx = (E₂ − E₁) / (S₀ − S̄f).

📊 Hydraulics Results

Configure inputs and click Compute to view results.

📘 Calculation Methodology & Open Channel Hydraulics

Backwater Curve Classification

Profiles are categorized by slope (Mild $M$, Steep $S$, Critical $C$) and zone ($1: y > y_n > y_c$, $2: y_n > y > y_c$, $3: y_c > y$).

Standard Step Integration Method

Solves specific energy balance across reach increments $\Delta x$, accounting for boundary friction dissipation and non-uniform velocity distribution.

Key Engineering Assumptions

  • Manning equation for reach-averaged friction slope $\bar{S}_f$.
  • Prismatic channel geometry with steady one-dimensional flow.
  • Applicable to river dam impoundments, canal drops, spillway chutes, and drainage systems.