**1 Answer**

written 5.2 years ago by |

Fluid is a substance which is capable of flowing OR Fluid is substance which deforms continuously under the influence of a shear or tangential force. OR The tendency to deform continuously is called fluidity and act of continuous deformation is called as flow.

Classification of fluids-

Ideal Fluid | Real Fluid |
---|---|

Fluids which don’t have viscosity and are incompressible are termed as ideal fluid such fluid do not offer shear resistance. | Fluids which do posses viscosity are termed as real fluids. These fluids always offer shear resistance. |

Real Fluid further classified into two types

**Newtonian fluid-**The fluids which obey Newton’s law of viscosity are called as Newtonian fluids such fluids exhibit linear relationship between shear stress and rate of angular deformation. Eg. - water , air etc.**Non-Newtonian Fluid-**Fluids which do not follow the linear relation between shear stress and rate of angular deformation are termed as Non Newtonian fluids. Hence for such fluids;

$$τ=constant×\bigg(\dfrac{dy}{dx}\bigg)^n.$$