Length of Weir Considering Bazin's Formula With Velocity of Approach Calculator

Bazin's Formula With Velocity of Approach:

\[ L_n = \frac{Q}{(0.405 + \frac{0.003}{l_a + h_a}) \times \sqrt{2g} \times (l_a + h_a)^{3/2}} \]

Discharge Weir (Q):

m³/s

Arc Length of Circle (lₐ):

Head Due to Velocity of Approach (hₐ):

Length of Notches (Lₙ):

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1. What is Bazin's Formula With Velocity of Approach?

Bazin's Formula With Velocity of Approach is used to calculate the length of notches in a weir, taking into account the velocity of approach. It provides an accurate measurement for hydraulic engineering applications where precise flow calculations are required.

2. How Does the Calculator Work?

The calculator uses Bazin's Formula:

\[ L_n = \frac{Q}{(0.405 + \frac{0.003}{l_a + h_a}) \times \sqrt{2g} \times (l_a + h_a)^{3/2}} \]

Where:

\( L_n \) — Length of Notches (m)
\( Q \) — Discharge Weir (m³/s)
\( l_a \) — Arc Length of Circle (m)
\( h_a \) — Head Due to Velocity of Approach (m)
\( g \) — Gravitational acceleration (9.80665 m/s²)

Explanation: The formula accounts for the combined effect of arc length and velocity head on the discharge capacity of the weir.

3. Importance of Weir Length Calculation

Details: Accurate calculation of weir length is crucial for proper hydraulic design, flood control, irrigation systems, and water resource management. It ensures optimal flow conditions and prevents overflow or underflow scenarios.

4. Using the Calculator

Tips: Enter discharge in m³/s, arc length in meters, and head due to velocity of approach in meters. All values must be positive numbers with appropriate units.

5. Frequently Asked Questions (FAQ)

Q1: What is the significance of velocity of approach in weir calculations?
A: Velocity of approach affects the effective head over the weir and therefore influences the discharge capacity. Ignoring it can lead to inaccurate flow calculations.

Q2: When should Bazin's formula be used instead of other weir formulas?
A: Bazin's formula is particularly useful when dealing with rectangular weirs and when the velocity of approach needs to be considered for more accurate results.

Q3: What are typical values for arc length and head in practical applications?
A: Values vary widely depending on the specific application, but arc lengths typically range from 0.5-10 meters, and head values from 0.1-2 meters in most civil engineering applications.

Q4: Are there limitations to Bazin's formula?
A: The formula assumes certain ideal conditions and may need adjustments for very large or very small weirs, or for non-standard weir shapes.

Q5: How does temperature affect the calculations?
A: Temperature affects water density and viscosity, but for most practical purposes, these effects are negligible in weir flow calculations.