ENGINEERING – HYDRAULIC & OPEN CHANNEL FLOW CALCULATOR
Circular Pipe Part Full
A precise tool.
What is the Circular Pipe Part Full & How does it work?
In a circular pipe that is not flowing completely full, the crossβsectional area is a circular segment. The segmentβs central angle (\theta) is related to the depth of flow (y) and the pipe diameter (D) by (\theta = 2\arccos\left(1-\frac{2y}{D}\right)). The wetted area can then be expressed analytically. The wetted perimeter (P) of the same segment is (P = \frac{D}{2}\theta). The hydraulic radius (R) follows as (R = A/P), which is a key parameter in openβchannel flow calculations. Manningβs equation links the hydraulic radius, pipe slope (S) and roughness coefficient (n) to the mean velocity: (V = \frac{1}{n}R^{2/3}S^{1/2}). Multiplying the velocity by the wetted area gives the discharge (Q = V A), allowing engineers to size pipes and predict performance under partially full conditions.
A = \frac{D^{2}}{8}\left(\theta – \sin\theta\right)
ΞΈ = 2\arccos\left(1-\frac{2y}{D}\right)
Parameters
Result
β
Frequently Asked Questions
How do I calculate the central angle ΞΈ for a circular pipe part full?
Use the formula ΞΈ = 2 * arccos(1 – (2y / D)), where y is the depth of flow and D is the pipe diameter.
What is the formula for the wetted area A in a circular pipe part full?
The wetted area A can be calculated using the formula A = (D^2 / 8) * (ΞΈ – sin(ΞΈ)), where ΞΈ is the central angle.
How do I find the wetted perimeter P of a circular pipe part full?
The wetted perimeter P is given by P = (D / 2) * ΞΈ, where ΞΈ is the central angle calculated from the depth of flow and diameter.
Can you explain what a circular segment is in this context?
A circular segment is the cross-sectional area of a circular pipe that is not flowing completely full, forming part of the circle’s circumference.
What are the units for depth of flow y and pipe diameter D?
The units for both depth of flow y and pipe diameter D should be consistent, typically in meters or inches.
Results are for informational purposes only and do not constitute professional advice.