How to calculate flow over a weir?
How to calculate flow over a weir?
The equation recommended by the Bureau of Reclamation in their Water Measurement Manual, for use with a suppressed rectangular weir is: Q = 3.33 B H3/2, where Q is the water flow rate in ft3/sec, B is the length of the weir (and the channel width) in ft, and H is the head over the weir in ft.
What is a circular weir?
Circular weirs are half-circle weirs that bolt onto the end of or inserted into conduits and pipes. Circular weirs are independent of the size of the conduit / pipe and typically require little in the way of installation accommodation.
What is a pipe weir?
A weir /wɪər/ or low head dam is a barrier across the width of a river that alters the flow characteristics of water and usually results in a change in the height of the river level.
What is a weir hydraulics?
A weir is a small dam built across a river to control the upstream water level. Over time, the term weir has taken on a more general definition in engineering to apply to any hydraulic control structure that allows water to flow over its top, often called its crest.
How do you calculate flow through AV notch weir?
The Equation
- The equation to determine the flow rate of a 90° Triangular Notch Weir is:
- = Flow Rate in cfs.
- = Height of the upstream water above the bottom of the weir in feet.
How do you calculate V notch?
The formula for the fully contracted V-notch weir is restricted to the following conditions:
- Head H < 1.25 ft (38 cm).
- Width B > 3 ft (91 cm).
- Height P > 1.5 ft (46 cm).
- Ratio b/H ≥ 2.0.
- Head/width ratio H/B ≤ 0.2.
What are the different types of weir?
Types of Weirs:
- Types of Weirs based on Shape of the Opening. Rectangular weir. Triangular weir. Trapezoidal weir.
- Types of Weirs based on Shape of the Crest. Sharp-crested weir. Broad- crested weir. Narrow-crested weir. Ogee-shaped weir.
- Types of weirs based on Effect of the sides on the emerging nappe.
What are some disadvantages of a weir?
Disadvantages of Weirs
- Spacious Upstream Weir Pool Required.
- Cold Weather Can Compromise Readings.
- Discharge Must Be Free-Spilling.
- Weir Maintenance Is Extensive.
- Weirs and Flumes From Tracom.
What is the difference between a weir and a dam?
Dams: A dam is a big wall constructed across a valley to control the flow or raise the level of water held within a catchment area. A weir is a steel or concrete barrier constructed across a river or creek that regulates water flow and allows water to be slowly released to users downstream.
What is weir and notch?
A notch means an opening provided in the side of a tank, such that the opening extends even above the free surface of the liquid in the tank. The weir is a notch cut in a dam to discharge the surplus quantity of water. Water flows over a notch or weir while water passes through an orifice.
What is purpose of a weir?
Weirs can be built to measure water flow rate, to alter the flow of rivers, or to prevent flooding. Additionally, small-size weirs can be used in large hydropower developments as a way to mitigate potential harm that may come about as a result of dam development.
How do you calculate V notch flow?
V Notch Weir Equation for Notch Angle Other than 90 Degrees That equation is: Q = 4.28 Ce Tan(θ/2)(H + k)5/2, where Q and H are as previously defined, θ is the angle of the v notch, Ce is the effective discharge coefficient, and k is a head correction factor.
