1. What is a Sharp Crested Weir?

A sharp crested weir is a thin plate installed perpendicular to flow in an open channel, used to measure or control water flow. The sharp crest ensures consistent flow characteristics for accurate measurement.

2. How Does the Calculator Work?

The calculator uses the sharp crested weir equation:

Where:

• \( q \) — Flow rate (m³/s)
• \( l \) — Length of weir crest (m)
• \( h \) — Head over weir crest (m)

Explanation: The equation relates the flow rate over the weir to the length of the weir and the height of water above the weir crest.

3. Importance of Weir Flow Calculation

Details: Accurate flow measurement is crucial for water resource management, irrigation systems, hydraulic engineering, and environmental monitoring.

4. Using the Calculator

Tips: Enter weir length and head over weir in meters. All values must be positive numbers. The weir must be fully aerated for accurate results.

5. Frequently Asked Questions (FAQ)

Q1: What are the limitations of this equation?
A: This simplified equation assumes free flow conditions, rectangular weir shape, and standard temperature. More complex equations exist for different conditions.

Q2: What is the typical range of application?
A: Generally valid for heads (h) between 0.03m and 0.75m, with h/l ratio less than 0.4.

Q3: How does weir shape affect the calculation?
A: Different coefficients apply for triangular (V-notch) or trapezoidal weirs. This calculator is for rectangular sharp crested weirs.

Q4: What is the coefficient 1.705 based on?
A: This empirical coefficient accounts for gravitational acceleration and assumes SI units (meters and seconds).

Q5: When should a more complex formula be used?
A: For submerged weirs, very small heads, or non-rectangular weirs, more specialized formulas should be used.