We
were discussing the basic concept of Lagrangian and Eulerian method and types of fluid flow in the subject of fluid mechanics in our recent posts. Now we
will start a new topic in the field of fluid mechanics i.e. discharge or flow
rate with the help of this post.

So
we will see here a very basic term used in fluid mechanics i.e. Discharge or
flow rate.

Flow rate is basically defined as the quantity of a fluid flowing through a section of pipe or channel per unit time.

Flow
rate or discharge = Quantity of fluid flowing through a section of pipe/Time

For
incompressible fluid, such as water, flow rate will be defined as the ratio of
volume of fluid flowing through the section and time.

For
compressible fluid, such as gas, flow rate will be defined as the ratio of weight
of fluid flowing through the section and time.

####
**Symbol**

Fluid
flow rate or discharge will be represented by Q.

###
**Unit of flow rate **

####
*For incompressible fluid
i.e. liquid*

*For incompressible fluid i.e. liquid*

Flow
rate or discharge = Volume of fluid flowing through a section of pipe/Time

Unit:
m

^{3}/s####
*For compressible fluid i.e.
gas*

*For compressible fluid i.e. gas*

Flow
rate or discharge = Weight of fluid flowing through a section of pipe/Time

Unit:
Newton/s or N/s

###
**
Mathematical form of
discharge or flow rate **

Let
us consider that we have one pipe of diameter D and water is flowing through
this pipe with a velocity of V. Flow rate of discharge through the section of the
pipe will be given by following formulas as mentioned here.

####
**Q
= A x V**

Where,
A is the area of cross-section of the pipe through which water is flowing

We
will now go ahead to discuss the concept of continuity equation in our next
post.

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

###
**
Reference:**

Fluid mechanics, By R. K. Bansal

Image
Courtesy: Google