Pipe Velocity Calculator Formula
Understand the math behind the pipe velocity calculator. Each variable explained with a worked example.
Formulas Used
Average Velocity
velocity = q_m3s / areaVariables
| Variable | Description | Default |
|---|---|---|
flow_rate | Volumetric Flow Rate (Q)(L/s) | 15 |
diameter | Pipe Inner Diameter(mm) | 100 |
q_m3s | Derived value= flow_rate / 1000 | calculated |
d_m | Derived value= diameter / 1000 | calculated |
area | Derived value= pi * pow(d_m, 2) / 4 | calculated |
How It Works
Pipe Flow Velocity
Velocity is derived from the continuity equation by dividing flow rate by cross-sectional area.
Formula
V = Q / A = 4 Q / (pi D^2)
where Q is the volumetric flow rate and D is the pipe inner diameter. Maintaining velocities within recommended ranges (1-3 m/s for water) avoids excessive pressure loss and erosion.
Worked Example
15 L/s flowing through a 100 mm diameter pipe.
flow_rate = 15diameter = 100
- 01Q = 15 L/s = 0.015 m^3/s
- 02A = pi x 0.1^2 / 4 = 0.007854 m^2
- 03V = 0.015 / 0.007854 = 1.91 m/s
Ready to run the numbers?
Open Pipe Velocity Calculator