## What is Fluid:

Any substance that flows or deforms under applied shear stress is called as fluid. The substances which have the tendency to flow is also called as fluid.

## Different types of fluids:

Fluids are classified into 5 different types which are as follows:

1. Ideal fluid

2. Real fluid

3. Newtonian fluid

4. Non-Newtonian fluid

5. Ideal plastic fluid

**1. Ideal Fluid:**

The fluid which cannot be compressed and have no viscosity falls in the category of an ideal fluid. Ideal fluid is not found in actual practice but it is an imaginary fluid because all the fluid that exists in the environment has some viscosity. So, there is no ideal fluid in reality.

**2. Real Fluid**:

A fluid that has some viscosity is called real fluid. Generally, all the fluids existing or present in the environment are called real fluids.

**3. Newtonian Fluid**

The Fluid which obeys Newton’s law of viscosity (i.e the shear stress is directly proportional to the shear strain) then it is known as the Newtonian fluid.

**4. Non-Newtonian Fluid **

The Fluid which does not obey Newtonâ€™s law of viscosity then it is called Non-Newtonian fluid.

**5. Ideal Plastic Fluid**

A fluid having the value of shear stress more than the yield value and shear stress is proportional to the shear strain (velocity gradient) is known as ideal plastic fluid.