Fluid Mechanics

Fluid Mechanics :- Fluid mechanics is that branch of science which deals with the behavior of fluids at a rest as well as in motion. Fluid Mechanics is that science which study the static, kinematic and dynamic behavior of fluids.

Properties of Fluids :-

1. Density or Mass Density :- Density or mass density of a fluid is defined as the ratio of mass of a fluid to its volume . Thus the mass par units volume of a fluid is called Density or mass density. It is denoted by p (rho). It's SI units is kg per cubic meter.

2. Specific weight or weight density :- Specific weight or weight density of a fluid may be defined as a ratio of the weight of fluid to the its volume. Thus the weight per unit volume of a fluid is called specific weight or weight density. It is denoted by 'w'. It's SI unit is Newton per unit cubic meter.

3. Specific Volume :- Specific volume of a fluid is defined as the volume occupied by the volume per unit mass . Thus the volume per unit mass of a fluid is termed as specific volume. It is the reciprocal of density or mass density.

4. Specific Gravity :- Specific gravity of a fluid is defined as the ratio of density of the fluid to the density of the standard fluid. Specific gravity is a dimensionless. It is denoted by 'S'.

Viscosity :- Viscosity is defined as the properties of fluid which offers a resistance to the one layer of the fluid to the another layer of the fluid is defined as the viscosity. It is denoted by 'tau'.

Newton's law of Viscosity :- It states that the shear stress of a liquid surface is directly proportion to the rate of shear strain. The constant of proportionalty is termed as a coefficient of viscosity.

Surface Tension :- Surface tension is defined as the tensile force acting on the surface of a liquid in a contact with the gas or on the surface of miscible two liquid surface. It is denoted by sigma.

Capillarity :- Capillarity is the phenomenon of rise and fall of a liquid surface in a small tube with the adjacent general level of liquid when small tube held in a vertical position in a liquid.

Types of Fluids :-

1. Ideal Fluids :- A fluid, which is incompressible and having no viscosity . It is an imaginary fluids because all fluids have a some viscosity.

2. Real Fluids :- A fluid , which have a viscosity are termed as Real fluids. In actual all fluids are Real fluids because all fluids having some viscosity.

3. Newtonian Fluids :- A real fluid, in which shear stress is directly proportion to the rate of shear strain is termed as a Newtonian fluids.

4. Non-Newtonian Fluids :- A real fluid, in which shear stress is not directly proportional to the rate of shear strain is known as Non-Newtonian fluids.

5. Real Plastics Fluids :- A fluid , in which shear stress is more than yields value and shear stress is directly proportional to the rate of shear strain.

Bulk Modulus of Elasticity :- It is defined as the ratio of compressive stress to volumetric strain. It is denoted by 'K'.

Compressibility :- Compressibility is the reciprocal of the bulk modulus of elasticity.

Kinematic Viscosity :- It is defined as the ratio between the dynamic viscosity and density of fluid. It is denoted by the Greek symbol (v) called 'nu'.