Discharge When End Contractions Is Suppressed And Velocity Is Considered Calculator

Francis Discharge with Suppressed End Formula:

\[ QFr' = 1.84 \times Lw \times (HStillwater^{3/2} - HV^{3/2}) \]

Francis Discharge with Suppressed End (QFr'):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is Francis Discharge with Suppressed End?

Francis Discharge with Suppressed End is the discharge of flow without the end contraction. It represents the flow rate over a weir when end contractions are eliminated, providing a more accurate measurement of water discharge in hydraulic engineering applications.

2. How Does the Calculator Work?

The calculator uses the Francis Discharge formula:

\[ QFr' = 1.84 \times Lw \times (HStillwater^{3/2} - HV^{3/2}) \]

Where:

\( QFr' \) — Francis Discharge with Suppressed End (m³/s)
\( Lw \) — Length of Weir Crest (m)
\( HStillwater \) — Still Water Head (m)
\( HV \) — Velocity Head (m)

Explanation: The formula calculates the discharge rate over a weir by considering the difference between the still water head and velocity head, both raised to the power of 3/2, multiplied by the length of the weir crest and the constant factor 1.84.

3. Importance of Discharge Calculation

Details: Accurate discharge calculation is crucial for hydraulic engineering, water resource management, irrigation system design, and flood control measures. It helps in determining the flow capacity of channels and designing appropriate water control structures.

4. Using the Calculator

Tips: Enter length of weir crest in meters, still water head in meters, and velocity head in meters. All values must be valid positive numbers (length > 0, still water head > 0, velocity head ≥ 0).

5. Frequently Asked Questions (FAQ)

Q1: What does "suppressed end" mean in this context?
A: Suppressed end means that the weir has no end contractions, meaning the weir extends across the full width of the channel, preventing side contractions that would reduce the effective length.

Q2: When should velocity head be considered in discharge calculations?
A: Velocity head should be considered when the approach velocity is significant enough to affect the accuracy of the discharge measurement, typically in channels with high flow velocities.

Q3: What are typical values for Francis Discharge?
A: Discharge values vary widely depending on weir dimensions and water head, but typically range from 0.1 to 100+ m³/s for practical engineering applications.

Q4: Are there limitations to this formula?
A: The formula assumes certain ideal conditions and may need adjustments for very small or very large weirs, unusual channel geometries, or extreme flow conditions.

Q5: How does this differ from standard Francis formula?
A: This formula specifically accounts for velocity head in the calculation, providing a more accurate result when approach velocity is significant, unlike the standard formula that may neglect this factor.