1. What is Discharge through Free Weir Portion?

Discharge through Free Portion refers to the fluid flow rate through the free section of a submerged weir, representing the quantity of water flowing between the upstream and downstream portions of the weir structure.

2. How Does the Calculator Work?

The calculator uses the simple subtraction formula:

Where:

• \( Q_1 \) — Discharge through Free Portion (m³/s)
• \( Q_T \) — Total Discharge of Submerged Weir (m³/s)
• \( Q_2 \) — Discharge through Drowned Portion (m³/s)

Explanation: The free portion discharge is calculated by subtracting the drowned portion discharge from the total discharge over the submerged weir.

3. Importance of Discharge Calculation

Details: Accurate discharge calculation is crucial for hydraulic engineering, water resource management, and flood control systems. Understanding the distribution of flow between free and drowned portions helps in proper weir design and operation.

4. Using the Calculator

Tips: Enter the total discharge and drowned portion discharge in cubic meters per second. Both values must be non-negative, and the total discharge must be greater than or equal to the drowned portion discharge.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between free and drowned weir flow?
A: Free flow occurs when the downstream water level is below the weir crest, while drowned flow occurs when the downstream water level submerges the weir crest, affecting the discharge characteristics.

Q2: What are typical units for discharge measurement?
A: Discharge is typically measured in cubic meters per second (m³/s) in SI units, or cubic feet per second (cfs) in imperial units.

Q3: When is a weir considered submerged?
A: A weir is considered submerged when the downstream water level rises above the weir crest, creating backwater effects that reduce the discharge capacity.

Q4: Are there limitations to this calculation method?
A: This simple subtraction method assumes accurate measurement of both total and drowned portion discharges. In practice, various factors such as weir shape, approach velocity, and water temperature can affect accuracy.

Q5: How is total discharge typically measured?
A: Total discharge can be measured using various methods including velocity-area method, weir equations, or flow meters, depending on the specific application and available equipment.