What is Fluid | Definition, Types-Classification of fluids
What is fluid mechanics ?
Introduction of Fluid Mechanics - Fluid Mechanics or Mechanics of Fluid is the branch of engineering science which deals with the behaviour of Fluids either subjected to different condition of pressure, friction resistance, rest, motion and flow.
Eg :- Gases, Liquid etc;
In the initial period of development of science, though much attention was paid on the motion of solid bodies the behaviour of fluids was also under study. This happened because it was a bit easy to treat a whole body as one particle because of the rigid connectivity of all the particles comprising the body, which was not so in the case of fluids where each particle has its own identity and independent motion. Therefore the study of the fluid flow was a much more complex process and its study gained.
In this Articles :-
Q. What is Fluid ?
Q. What is Fluid Mechanics ?
Q. Classification of Fluid.
Q. Definition of Statics, Kinematics, Dynamics Fluid.
Q. Definition of Newtonian Fluid, Non - Newtonian Fluid, Ideal Fluid, Real Fluid
What is Fluid ?
Introduction of Fluid - Fluid is a substance that deform continuously under the action of shear stress.
Fluid - Fluid is defined as a substance which is capable of flowing from one point to another point under the action of shear stress, If allowed to do so. It changes it's shape with very little exerted force. Fluid exist on liquid and gases. Fluid is everywhere, in the atmosphere and around the aircraft, blood circulation of the human body and ocean .
Examples of fluid - Water, Air, Blood, Gasoline, Mercury, Honey and other gases and liquid.
A Fluid is no definite shape an it takes the shape of the container in which it is contained shearing force, on a fluid change it's shape when shearing force act on a fluid, the fluid will flow if a fluid is at rest there can be no shearing force on it
Fluid Consists of :-
1. Statics Fluid
2. Kinematics Fluid
3. Dynamic Fluid
(1.) Statics Fluid :-
The statics fluid is defined as that branch of science which deals with the study of mechanics of fluid at absolute and relative rest is called Statics fluid. In Statics fluid shear stress is always zero .
Examples of statics fluid - Water in dam, pipes etc.
(2.) Kinematics Fluid :-
The kinematics fluid is defined as that branch of science which deals with the study of mechanics of fluid is pure motion without any pressure or motion is called Kinematics fluid.
(3.) Dynamic Fluid :-
The dynamics of fluid flow is defined as that branch of science which deals with the study of mechanics of fluid in motion considering the forces which cause the flow is called Fluid Dynamics.
Examples of dynamics fluid -
➤ Flow through the pipes
➤ Laminar & Turbulent flow
➤ Flow hrough notch & weirs
➤ Orifice & mouth pieces
Classification of fluids :-
Generally fluids are classified into four types :-
1. Newtonian Fluid
2. Non - Newtonian Fluid
3. Ideal Fluid
4. Real Fluid
1. Newtonian Fluid :-
These type of fluid is obey the newton law of viscosity, Newtonian fluid is the fluid in which the shear stress is directly proportional to the rate of shear strain and velocity gradient. and these type of fluid whose viscosity doesn't change with the rate of deformation or shear strain.
Ex :- Glycerine, alcohal, water, air and all types of gases,
The linear relationship between shear stress and the rate of deformation is also called Newtonian fluid.
2. Non - Newtonian Fluid :-
These fluid which does not obey the newton law of viscosity, Non - Newtonian fluid whose viscosity change with the rate of deformation or shear strain. and these type of fluid which shear stress is not directly proportional to the rate of shear strain or velocity gradient is called as Non - Newtonian fluid.
Ex :- Gel, Toothpaste , lubricant oils.
The Non-liner relationship between shear stress and the rate of deformation is also called Non - Newtonian fluid.
In Pseudo plastics - n<1 , B=0 Ex-Blood milk.
In Dilatant - n>1 , B=0 Ex- Butter,honey, Quick sand.
In Ideal plastics - n=1 , B≠0 Ex- Tooth paste, Gel, Jam, Sewage, Sludge.
In Thixotropic - n<1 , B≠0 Ex- Printer ink, Enamel paint.
In Rheopecticc - n>1 , B≠0 Ex- Gypsum water solution, Bentonite Solution.
Note - Study of Non - Newtonian Fluid is called Rheology.
3. Ideal Fluid :-
A fluid which is no viscosity and surface tension and which are incompressible is known as ideal fluid. It is imaginary fluid and do no exist in nature.
4. Real Fluid :-
A fluid which have viscosity, surface tension and compressible is known as real fluid.
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