We were
discussing the various types of notches and weirs i.e. classifications of
notches and weirs, difference between Notches
and Weirs and
also the expression for discharge over a rectangular notch or weir, in the
subject of fluid mechanics, in our recent posts.

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Now we
will go ahead to find out the discharge over a triangular notch or weir, in the
subject of fluid mechanics, with the help of this post.

We must
note it here that the expression of the discharge over a triangular notch or
over a weir will be same.

Now, let
us consider that we have channel carrying water and let us think a triangular notch
or weir with this channel as displayed here in following figure.

We have
following data from above figure and these data are as mentioned here

H = Head
of water above the V-notch

Î¸ = Angle
of notch

Let us
consider one elementary horizontal strip of water of thickness dh and at a
depth of h from free surface of water as displayed here in above figure.

dh =
Thickness of elementary horizontal strip of water flowing over the triangular
notch or weir

h = Depth
of elementary horizontal strip of water from free surface of water

C

_{d}= Co-efficient of discharge
We will determine
the value of discharge dQ through the elementary horizontal strip of water. After
securing the expression for discharge through the elementary horizontal strip,
we will integrate the expression between the limit 0 to H and we will have the
expression for the discharge over entire triangular notch or weir.

dQ = C

_{d}x Area of strip x Theoretical velocity**Area of strip**

First we will secure the value of area of horizontal
elementary strip

Now we will secure here the expression for

Now we
will go ahead to start a new topic in the subject of fluid mechanics i.e. Advantages of triangular notch or weir over rectangular notch or weir over.

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

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**Reference:**** **

Fluid
mechanics, By R. K. Bansal

Image Courtesy:
Google