Table of Contents
- 1 What are the applications of weirs?
- 2 What is the purpose of coefficient of discharge?
- 3 What is meant by coefficient of discharge CD?
- 4 What are the factors that affect the coefficient of discharge?
- 5 What are the applications using rectangular notches?
- 6 How is weir coefficient calculated?
- 7 How is a weir used in practical engineering?
- 8 What are the factors that affect the discharge coefficient?
What are the applications of weirs?
Commonly, weirs are used to prevent flooding, measure water discharge, and help render rivers more navigable by boat.
What is the purpose of coefficient of discharge?
The discharge coefficient is a dimensionless number used to characterise the flow and pressure loss behaviour of nozzles and orifices in fluid systems. Orifices and nozzles are typically used to deliberately reduce pressure, restrict flow or to measure flow rate.
What is the coefficient of discharge for a weir?
The flat-topped low weirs generally include broad-crested weir and short-crested weir. Under the same inflow condition, the discharge coefficient of short-crested weir is approximately 0.33–0.46, while that of broad-crested weir is 0.32–0.385, hence the former is stronger than the latter in terms of discharge capacity.
Does the length of weir affect the discharge coefficient?
Results indicated that by increasing the weir height, the discharge capacity increased. One type of long-crested weir is oblique weir. Oblique weirs are longer than standard weirs. Therefore, they can pass more discharge capacity than weirs at the given channel width.
What is meant by coefficient of discharge CD?
Coefficient of discharge is stated as the ratio between the actual flow discharge and theoretical flow discharge. It is symbolized by Cd and its value is different for each fluid depending on the kind of measurement of flow.
What are the factors that affect the coefficient of discharge?
What are the applications using these notches?
The applications of notch include tanks, reservoirs, or any water storage devices that have a passage for water escape. Similarly, a weir is a notch on a large scale used to measure flows of rivers and canals. Apart from measuring, notch and weir are also used to regulate the discharge of small and large channels.
How is weir discharge coefficient calculated?
In Equation (14.18) the discharge coefficient C d = ( 2 / 3 ) ( 2 g / 3 ) = 1.705 in metric units and, in Equation (14.19), C ′ d = ( 2 / 3 ) 2 / 3 = 0.544 in non-dimensional units. If the flow passes through critical depth over a weir crest then it might appear that Cd would always take that value.
What are the applications using rectangular notches?
Rectangular notches and Triangular notches are often used in water supply, wastewater and sewage systems. They consist of a sharp edged plate with a rectangular, triangular or v-notch profile for the water flow.
How is weir coefficient calculated?
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.
How are the coefficients of discharge determined in a weir?
The coefficients of discharge are determined by measuring the height of the water surface above the notch base and the corresponding flow rate. The general features of the flow can be determined by direct observation. 5. Equipment
How are weirs used to measure river flow?
Weirs are commonly used to measure or regulate flow in rivers, streams, irrigation canals, etc. Installing a weir in an open channel system causes critical depth to form over the weir. Since there is a unique relationship between the critical depth and discharge, a weir can be designed as a flow-measuring device.
How is a weir used in practical engineering?
Hey I’m Grady and this is Practical Engineering. On today’s episode, we’re talking about wiers. A weir is a small dam built across a river to control the upstream water level. Weirs have been used for ages to control the flow of water in streams, rivers, and other water bodies.
What are the factors that affect the discharge coefficient?
The discharge coefficient, C0, is influenced by a number of factors. These factors are: the effect of the approach depth, the effect of heads different from the design head, the effect of the upstream face slope, the effect of the downstream apron interference, and the effect of the downstream submergence.