Partially FULL Pipe Flow Calculator and Equations

Fluid Flow Table of Contents
Hydraulic and Pneumatic Knowledge
Fluid Power Equipment

This engineering calculator determines the Flow within a partially full pipe (&e1/2 full using the Manning equation. This calculator can also be used for uniform flow in a pipe, but the Manning roughness coefficient needs to be considered to be variable, dependent upon the depth of flow.

Partially Full Pipe Flow Parameters

Chart Flow in PArtially Full Pipes


r = D/2

h = 2r - y y/D

Hydraulic Radius
R = A/P

Manning Equation
Q = (1.49/n)(A)(R 2/3 )(S1.2 )
V = Q/A

Partially Full Pipe Formulas for Flow

Equation used for n/nfull = 1.25 - ( y/D - 0.5) * 0.5 (for 0.5 ≤ y/D ≤ 1 )