Information about fluid

Fluid :-

          Fluid is a substance which is capable to flow.

Classification of fluid :

                                                                  

Isotropic substance

                    Fluid is treated as isotropic substance which implies that physical property(i.e pressure, density etc) is same in all direction.

Anisotropic substance

                    Fluid is treated as anisotropic substance if that  property is not same in all direction.

Newtonian fluid

The fluid which obeys Newtonian relationship between shearing stress and gradient of velocity given by

                        

where  
 is the velocity gradient and τ is shearing stress.

Ideal fluid

Ideal fluid is a Newtonian fluid in which there exist no shearing or tangential stress but exist only normal or direct stress between two contacting layers.

Note that in nature ideal fluid doesn’t occur. They are only as mathematical concept.

Real  fluid

Real fluid is a Newtonian fluid in which there exist both tangential and normal stress between two contacting layers.