Hydraulics & Fluid Mechanics
Weir Flow Simulator
A dynamic hydraulics laboratory to simulate free-surface flow over a rectangular suppressed weir. Control weir geometry, head over crest, and discharge presets to visualize nappe profiles, crest velocities, and flow curves.
Weir Type
Sharp-Crested
Cd = 0.60
Discharge
1.25 m³/s
Free discharge
Daily Output
108.2 ML/d
Estimated volume
Parameters
Weir Preset Type
Animated head sweep
Governing Equations
Francis Equation (Weir Flow)
Q = (2/3) * Cd * L * sqrt(2g) * H^1.5
Flow Velocity at Crest
V = Q / (L * H)
Flow Cross-Sectional Area
Ac = L * H
At the current head H = 0.50 m, the flow area is 1.00 m².
The average velocity over the crest is estimated at 1.25 m/s.
Francis Formula assumes a rectangular suppressed weir with vertical faces and free discharge (no downstream submergence).
Linked Flow Diagram
Flow Rate (Q)
1.253m³/s
Daily Volume
108.25ML/day
Crest Velocity
1.25m/s
Crest Flow Area
1.00m²
Flow Rate & Velocity vs Head
Simulation Data
| Head H (m) | Flow Rate (m³/s) | Velocity (m/s) | Daily Volume (ML/d) |
|---|---|---|---|
| 0.05 | 0.040 | 0.40 | 3.4 |
| 0.25 | 0.443 | 0.89 | 38.3 |
| 0.45 | 1.070 | 1.19 | 92.4 |
| 0.65 | 1.857 | 1.43 | 160.4 |
| 0.85 | 2.777 | 1.63 | 239.9 |
| 1.05 | 3.813 | 1.82 | 329.4 |
| 1.25 | 4.952 | 1.98 | 427.9 |
| 1.45 | 6.187 | 2.13 | 534.6 |
| 1.65 | 7.510 | 2.28 | 648.9 |
| 1.85 | 8.917 | 2.41 | 770.4 |
| 2.05 | 10.401 | 2.54 | 898.6 |
| 2.25 | 11.960 | 2.66 | 1033.3 |
| 2.45 | 13.589 | 2.77 | 1174.1 |
| 2.65 | 15.287 | 2.88 | 1320.8 |
| 2.85 | 17.049 | 2.99 | 1473.1 |