Discharge For Entire Triangular Weir Calculator

Triangular Weir Formula:

\[ Q_{tri} = \frac{8}{15} \times C_d \times \sqrt{2g} \times \tan\left(\frac{\theta}{2}\right) \times H_w^{5/2} \]

Coefficient of Discharge (Cd):

Acceleration due to Gravity (g):

m/s²

Angle (θ):

radians

Height of Water above Crest (Hw):

meters

Discharge through Triangular Weir (Qtri):

m³/s

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1. What is the Triangular Weir Discharge Formula?

The triangular weir discharge formula calculates the volumetric flow rate of water through a V-shaped (triangular) weir opening. This equation is commonly used in hydraulic engineering for flow measurement in open channels.

2. How Does the Calculator Work?

The calculator uses the triangular weir formula:

\[ Q_{tri} = \frac{8}{15} \times C_d \times \sqrt{2g} \times \tan\left(\frac{\theta}{2}\right) \times H_w^{5/2} \]

Where:

\( Q_{tri} \) — Discharge through triangular weir (m³/s)
\( C_d \) — Coefficient of discharge (dimensionless)
\( g \) — Acceleration due to gravity (m/s²)
\( \theta \) — Angle of the V-notch (radians)
\( H_w \) — Height of water above crest of weir (m)

Explanation: The formula accounts for the geometric properties of the triangular weir and the hydraulic characteristics of the flow.

3. Importance of Triangular Weir Calculation

Details: Accurate discharge calculation through triangular weirs is essential for water resource management, irrigation system design, hydraulic structure design, and environmental flow monitoring.

4. Using the Calculator

Tips: Enter the coefficient of discharge (typically 0.58-0.62 for triangular weirs), acceleration due to gravity (9.8 m/s² standard), weir angle in radians, and water height above the crest. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical range for coefficient of discharge?
A: For triangular weirs, Cd typically ranges from 0.58 to 0.62, depending on the weir geometry and flow conditions.

Q2: How do I convert degrees to radians?
A: Multiply degrees by π/180 (approximately 0.0174533). A 90° angle equals π/2 radians (approximately 1.5708).

Q3: What are common weir angles used in practice?
A: Common angles are 90°, 60°, and 45° V-notches, with 90° being the most frequently used.

Q4: What are the limitations of triangular weirs?
A: Triangular weirs are less accurate for very low flows and may be affected by approach velocity, weir crest conditions, and water surface turbulence.

Q5: How does water height affect the discharge?
A: Discharge is proportional to H_w^(5/2), meaning small changes in water height result in significant changes in discharge rate.