What is the difference between rectangular notch and V notch?
Olivia House What is rectangular notch?
The rectangular weir (notch) is a common device used to regulate and measure discharge in irrigation projects. The current research was based mainly on laboratory experiments studying the hydraulic characteristics of rectangular notches. Four rectangular notches were used in this research in different models.
Which notch is accurate?
The results of which are more accurate; rectangular notch or triangular weir. Explanation: The results of triangular notch are more accurate for low discharge.
Which is better triangular or rectangular notch?
Answer: A triangular notch is also called a V- notch. A triangular notch gives more accurate results for low discharges than rectangular notch and the same triangular notch can measure a wide range of flow.
What is the difference between rectangular weir plate and V-notch weir plate?
Asstated in the theory, rectangular weir is able to measure higher flows thanthe V-notch weir over a wider operating range while V-notch weir typicallyused to measure low flows within a narrow operating range.
Flow Measurement: Weirs
What is a V notch?
What is a V notch weir? V notch weirs really are just that – a thin plate weir with a 'V' notch cut into it. The weir is placed to obstruct open channel flow and allow water to flow over the notch. This enables us to accurately measure the flow, by measuring the head upstream of the V notch.
Why V notch is more accurate than rectangular notch?
V-notch will provide more precise results during measuring low discharge as compare to result obtained from rectangular notch. Because rectangular notch area is greater than V-notch. So the Depth of the V- notch is high.
Which notch gives more accurate results?
For measuring the low discharge, a triangular notch gives more accurate results than a rectangular. In the case of the triangular notch, only one reading i.e H is required for the computation of discharge.
Why do we use V notch?
It is used to meter flow of water in the channel, by measuring the head of water over the v notch crest. The v notch weir is especially good for measuring a low flow rate, because the flow area decreases rapidly as the head over the v notch gets small.
What is the main advantage of V notch weir?
Because the V-notch weir has no horizontal crest length, the head required for a small flow through it is greater than that required with the other weir types. This greater head is an advantage because nappes of smaller discharges will spring free of the crest.
What are different types of notches?
Types Of Notches
- Rectangular notch.
- Triangular notch.
- Trapezoidal notch.
- Stepped notch.
What are the applications of rectangular notch?
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.
Why is V-notch used in Charpy?
The point is to promote the condition of brittle fracture. The notch here acts as a stress riser and favours the crack propagation.
Why does the V-notch give more accurate flow measurement?
V-notch gives more accurate results for low dischargecoefficientcompared to rectangularnotch. This is due to the space for the water to flow throughthe notch. For rectangular notch, the space of water it is constant for every depth.
How is V-notch measured?
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 is calibration of V notch?
A Notch is regarded as an orifice with water level below its upper edge. Notch is made of a metallic plate and its use is to measure the discharge of liquids. These are used for measuring the flow of water from a vessel or tank with no pressure flow.
What is difference between notch and weir?
A notch may be defined as an opening provided in the side of tank or vessel such that the liquid surface in tank is below the top edge of opening. A weir may be defined as any regular obstruction in open stream over which the flow takes place. Made of metallic plates.
What is V notch Borewell?
A common way to describe the yield of a new borewell is in 'inches' measured by the free, unrestrained flow of water from a borewell over a 90 degree 'V' notch. The basic principle is that the discharge is directly related to the height of the water level from the bottom of the V notch.
Where is triangular notch used?
The triangular-notch, thin-plate weir is a convenient, inexpensive, and relatively precise flow-measuring instrument. It is frequently used to measure the flow of water in laboratories and in small, natural streams.
What is the advantage of triangular notch or weir over rectangular notch?
Triangular notch will provide more precise results during measuring low discharge as compare to result obtained from rectangular notch. Only one reading of H will be required for determination of discharge in case of triangular notch.
What is trapezoidal notch?
A trapezoidal notch is a combination of a rectangular notch and two triangular notches as shown in figure. It is, thus obvious that the discharge over such a notch will be the sum of the discharge over the rectangular and triangular notches.
What is weir box?
Definition of weir box
: a wooden or concrete box oblong in shape and open at both ends which is set lengthwise in a canal and in which a weir for the measurement of irrigation water is set crosswise.
Which type of weir is best?
Triangular weir:
This type of weirs are well suitable for measuring discharge over small flows with greater accuracy.
Which type of notch is more advantageous?
Advantages of Triangular Notch(V-notch) over Rectangular Notch : For measurement of discharge in V-notch only one reading i.e. head(H) is required. For low discharge V-notch gives greater head than rectangular notch. Hence, accuracy is more for V-notch.
