## Saturday, 23 June 2018

We were discussing the difference between streamline and equipotential lineModals law or similarity lawmomentum equations and Bernoulli’s equation from Euler’s equation, in the subject of fluid mechanics, in our recent posts.

Now we will go ahead to understand the basics of orifices and mouthpieces with the help of this post. We will understand here first the difference between orifice and mouthpiece.

So let us come to the main topic, without wasting your time.

### Orifice

Orifice is basically a small opening of any cross-section such as triangular, square or rectangular on the side or at the bottom of tank, through which a fluid is flowing.

Orifice is basically used in order to determine the rate of flow of fluid.

As we have discussed above that orifice will be a small opening of any cross-section, hence flow through the orifice will be very small.

#### Orifices are basically classified on the basis of

Shape of orifice
Size of orifice
Shape of edge
Nature of discharge
On the basis of sub-merged condition e.g. fully sub-merged orifices and partially sub-merged orifices

### Mouthpiece

Mouthpiece is basically a small length of pipe which will be installed with the tank or vessel containing the fluid. Length of this small pipe will be approximate two to three times of its diameter.

Mouthpiece is basically used in order to determine the rate of flow of fluid.

Dimension of mouthpiece will be comparatively larger than the dimension of orifice. Therefore, flow through the mouthpiece will be quite larger as compared with flow through the orifice.

Mouthpiece is also used, in some cases, in order to increase the discharge through the orifice.

#### Mouthpieces are basically classified on the basis of

Mouthpieces are classified on the basis of their position with respect to the tank e.g. External mouthpieces and internal mouthpieces.

Mouthpieces are also classified on the basis of their shape e.g. cylindrical mouthpieces, convergent mouthpieces and convergent-divergent mouthpieces.

Mouthpieces are also classified on the basis of nature of discharge at the outlet of mouthpiece e.g. mouthpieces running full and mouthpieces running free.

Now we will go ahead to discuss the various classifications of orifices and mouthpieces, 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