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Sunday, 29 July 2018

CLASSIFICATION OF NOTCHES AND WEIRS

We were discussing the basic concepts and also difference between Notches and Weirs in the subject of fluid mechanics in our recent posts. 

Now we will go ahead to find out the various classifications of Notches and Weirs with the help of this post. 

Notch 

Notch is basically defined as a device which is used for determining the flow of liquid through a small channel or a tank. 

Notches might be defined as the opening provided in one side of a tank or reservoir or a small channel in such a way that the liquid surface in the tank or channel is below the top edge of opening. 

Classification of notches 

There are following types of notches on the basis of shape of opening and these are as mentioned here 
Rectangular Notch 

Triangular Notch or V- notch 
Trapezoidal Notch 
Stepped Notch 

There are following types of notches on the basis of the effect of sides on the nappe and these are as mentioned here 

  1. Notch with end contraction 
  2. Notch without end contraction or suppressed notch 

Weir 

A weir will be basically a concrete or masonary structure which will be located in an open channel over which flow will take place. 

We can also define as the structure constructed across the river or large canal for storing water on upstream side. 

Weir will be usually in the form of vertical wall, with a sharp edge at the top, running all the way across the open channel. 

Classification of weirs 

There are following types of weirs on the basis of shape of opening and these are as mentioned here 

  1. Rectangular weir 
  2. Triangular weir 
  3. Trapezoidal or Cippoletti weir 

There are following types of weirs on the basis of shape of the crest and these are as mentioned here 

  1. Sharp crested weir 
  2. Broad crested weir 
  3. Narrow crested weir 
  4. Ogee shaped weir  

There are following types of weirs on the basis of the effect of sides on the emerging nappe and these are as mentioned here 

  1. Weirs with end contraction 
  2. Weirs without end contraction or suppressed notch 

Now we will go ahead to find out the classifications of notches and weirs, in the subject of fluid mechanics, in our next post. 

Do you have any suggestions? Please write in comment box. 

Reference: 

Fluid mechanics, By R. K. Bansal 
Image Courtesy: Google