Discharge Over Broad Crested Weir Calculator

Discharge Over Broad Crested Weir Formula:

\[ Q_w = L_w \times h_c \times \sqrt{2 \times g \times (H - h_c)} \]

Discharge Over Broad Crested Weir (Q_w):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is Discharge Over Broad Crested Weir?

Discharge Over Broad Crested Weir is a measure of the quantity of any fluid flow over unit time. The quantity may be either volume or mass. It is calculated for weirs with a broad crest where the flow is critical over the crest.

2. How Does the Calculator Work?

The calculator uses the Discharge Over Broad Crested Weir formula:

\[ Q_w = L_w \times h_c \times \sqrt{2 \times g \times (H - h_c)} \]

Where:

\( Q_w \) — Discharge Over Broad Crested Weir (m³/s)
\( L_w \) — Length of Weir Crest (m)
\( h_c \) — Critical Depth of Weir (m)
\( H \) — Total Head (m)
\( g \) — Gravitational acceleration (9.80665 m/s²)

Explanation: The equation calculates the discharge over a broad crested weir based on the length of the weir crest, critical depth, total head, and gravitational acceleration.

3. Importance of Discharge Calculation

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

4. Using the Calculator

Tips: Enter length of weir crest in meters, critical depth in meters, and total head in meters. All values must be valid positive numbers, and total head must be greater than critical depth.

5. Frequently Asked Questions (FAQ)

Q1: What is a broad crested weir?
A: A broad crested weir is a type of flow measurement structure with a horizontal crest that is sufficiently long in the direction of flow to cause the flow to become critical over the crest.

Q2: When is this formula applicable?
A: This formula is applicable when the weir crest is broad enough to establish parallel flow with critical depth over the crest, and when the upstream head is measured sufficiently far from the weir.

Q3: What are the limitations of this formula?
A: The formula assumes ideal flow conditions, neglects viscosity and surface tension effects, and requires accurate measurement of head and crest length.

Q4: How does critical depth affect the discharge?
A: Critical depth represents the depth at which the specific energy is minimum for a given discharge. It plays a crucial role in determining the flow characteristics over the weir.

Q5: Can this formula be used for all types of weirs?
A: No, this formula is specifically designed for broad crested weirs. Other weir types (sharp crested, ogee, etc.) require different discharge equations.