Fluid Mechanics - Study of fluids and its properties and behaviours during flow and non flow.
What is Fluid ?
Substance that can flow from one point to another point are called fluid.
It takes the shape of the container . It don’t have its own shape.
Two type of fluids are
1. Gas Fluid - gas fluid can be compressed (compressible)
2. Liquid Fluid - liquid fluids are incompressible ( cannot be compressed)
Fluid Mechanics Sub Division
1 Hydro Statics - Study of fluid and its characteristics in static condition or (while not flowing )
2 Hydro Kinematics - Study of fluid and its characteristics without considering pressure acts in it.
3.Hydro Dynamics - Study of fluid characteristic considering the pressure acts in it.
Fluid Types according to its state
1. Perfect Fluid or Ideal Fluid
2. Real Fluid
3. Newtonian Fluid
4. Non- Newtonian Fluid
No fluid is perfect. Therefore every fluid has viscosity which develop resistance to flow of liquid. It is an imaginary fluid.
A fluid when flow does not give resistance and if it is incompressible then it is called Ideal Fluid or Perfect Fluid
Real fluid that has its characteristics’ such as viscosity, surface tension,cohesion,compressibility then it is called real fluid. In practice all fluids are real fluids – water,oil etc.
If the shear stress induced in the fluid is directly proportionally equal to the shear strain then it is called Newtonian fluid. – water,oil, air ( They obey the laws of Newton)
If the shear stress induced in the fluid is directly proportionally not equal to the shear strain then it is called Non-Newtonian fluid. – paint, melted plastics ( They donot obey the laws of Newton)
Properties of Fluid
1. Pressure
2. Density
3. Specific Volume
4. Specific Weight
5. Relative Density
6. Compressibility
7. Capillarity
8. Surface tension
9. Viscosity
10. Cohesion
11. Adhesion
Pressure
Force acting at point ( in an unit area) in a fluid is intensity of pressure/static pressure
Force/ area Total Pressure/ area symbol is p unit N/m2 1 Pa = 1Nm 1bar = 105 Pa
Density
Ratio between mass of the fluid and its volume
mass/ volume symbol is ρ unit kg/m3 Hg pressure 13600 water 1000 at 4⁰c
Relative Density
Ratio between the density of a fluid and the density of (standard fluid) water.
In case of liquid water is taken as standard fluid
In case of gas air is taken as standard fluid
In general density of a liquid = s x density of water s x 1000 kg/ m3
Relative Density s = Density of Fluid/ Density of Standard
What is Fluid ?
Substance that can flow from one point to another point are called fluid.
It takes the shape of the container . It don’t have its own shape.
Two type of fluids are
1. Gas Fluid - gas fluid can be compressed (compressible)
2. Liquid Fluid - liquid fluids are incompressible ( cannot be compressed)
Fluid Mechanics Sub Division
1 Hydro Statics - Study of fluid and its characteristics in static condition or (while not flowing )
2 Hydro Kinematics - Study of fluid and its characteristics without considering pressure acts in it.
3.Hydro Dynamics - Study of fluid characteristic considering the pressure acts in it.
Fluid Types according to its state
1. Perfect Fluid or Ideal Fluid
2. Real Fluid
3. Newtonian Fluid
4. Non- Newtonian Fluid
No fluid is perfect. Therefore every fluid has viscosity which develop resistance to flow of liquid. It is an imaginary fluid.
A fluid when flow does not give resistance and if it is incompressible then it is called Ideal Fluid or Perfect Fluid
Real fluid that has its characteristics’ such as viscosity, surface tension,cohesion,compressibility then it is called real fluid. In practice all fluids are real fluids – water,oil etc.
If the shear stress induced in the fluid is directly proportionally equal to the shear strain then it is called Newtonian fluid. – water,oil, air ( They obey the laws of Newton)
If the shear stress induced in the fluid is directly proportionally not equal to the shear strain then it is called Non-Newtonian fluid. – paint, melted plastics ( They donot obey the laws of Newton)
Properties of Fluid
1. Pressure
2. Density
3. Specific Volume
4. Specific Weight
5. Relative Density
6. Compressibility
7. Capillarity
8. Surface tension
9. Viscosity
10. Cohesion
11. Adhesion
Pressure
Force acting at point ( in an unit area) in a fluid is intensity of pressure/static pressure
Force/ area Total Pressure/ area symbol is p unit N/m2 1 Pa = 1Nm 1bar = 105 Pa
Density
Ratio between mass of the fluid and its volume
mass/ volume symbol is ρ unit kg/m3 Hg pressure 13600 water 1000 at 4⁰c
Relative Density
Ratio between the density of a fluid and the density of (standard fluid) water.
In case of liquid water is taken as standard fluid
In case of gas air is taken as standard fluid
In general density of a liquid = s x density of water s x 1000 kg/ m3
Relative Density s = Density of Fluid/ Density of Standard