Discharge Over Rectangle Weir For Bazin's Formula With Velocity Of Approach Calculator

Bazin's Formula with Velocity of Approach:

\[ Q = \left(0.405 + \frac{0.003}{H + h_a}\right) \times L_w \times \sqrt{2g} \times (H + h_a)^{3/2} \]

Discharge Weir (Q):

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1. What is Bazin's Formula for Rectangular Weir?

Bazin's formula is an empirical equation used to calculate the discharge over a rectangular weir, accounting for the velocity of approach. It provides a more accurate estimation of flow rate compared to basic weir formulas.

2. How Does the Calculator Work?

The calculator uses Bazin's formula with velocity of approach:

\[ Q = \left(0.405 + \frac{0.003}{H + h_a}\right) \times L_w \times \sqrt{2g} \times (H + h_a)^{3/2} \]

Where:

\( Q \) — Discharge over weir (m³/s)
\( H \) — Head of liquid above weir crest (m)
\( h_a \) — Head due to velocity of approach (m)
\( L_w \) — Length of weir (m)
\( g \) — Gravitational acceleration (9.80665 m/s²)

Explanation: The formula accounts for the approach velocity effect on discharge calculation, providing more accurate results for practical engineering applications.

3. Importance of Discharge Calculation

Details: Accurate discharge calculation is crucial for hydraulic engineering, irrigation systems, water resource management, and flood control design.

4. Using the Calculator

Tips: Enter head of liquid and head due to velocity of approach in meters, length of weir in meters. All values must be positive (head > 0, length > 0).

5. Frequently Asked Questions (FAQ)

Q1: What is the velocity of approach?
A: Velocity of approach refers to the velocity of water approaching the weir, which affects the discharge calculation and is accounted for by the head due to velocity.

Q2: When should Bazin's formula be used?
A: Bazin's formula is particularly useful when the approach velocity is significant and needs to be considered for accurate discharge estimation.

Q3: What are typical values for head due to velocity?
A: The head due to velocity typically ranges from 0.1 to 1.0 meters, depending on the approach channel characteristics and flow conditions.

Q4: Are there limitations to this formula?
A: The formula assumes a well-defined weir crest, free flow conditions, and may have reduced accuracy for very small or very large heads.

Q5: How accurate is Bazin's formula?
A: Bazin's formula provides good accuracy for practical engineering purposes, typically within ±5% of actual measured discharges.