Property of fluid

1. DEPARTMENT OF MECHANICAL ENGINEERING
BUDGE BUDGE INSTITUTE OF TECHNOLGY
NISCHINTAPUR, BUDGE BUDGE – 700137, W.B
January 2023
Topic for CA 1: “Properties of fluid”
Student Name Prince Gupta
University Roll No : 27600720034
Department : Mechanical Engineering
Year of Study : 4th Year 8 Semester
Subject Name : Analysis and performance
of Fluid Machines – (PE ME801A)

2. What is a Fluid ?
Fluids undergo continuous deformation, i.e. fluids always keep flowing. Fluid is a substance that
does not possess a definite shape and easily yields to external pressure. Fluid is any liquid or gas
or any material that is unable to withstand a shearing or tangential force, when at rest. When
the said forces are applied to the fluid, it goes through a continuous change in shape. Fluids are
substances with zero shear modulus, i.e they cannot resist the shear force applied to them.
In our day-to-today life, we would have heard the dehydrated patient advised to consume more
fluids to compensate for the water loss. Fluids help in the digestion of food, hence we need to
take more fluids.
Classification of Fluids
Fluids are classified into four types
depending on their flow, they are:
1. Steady or unsteady
2. Compressible or incompressible
3. Viscous or non-viscous
4. Rotational or irrotational

3. Properties of Fluids :
After understanding what is fluid and its classification,
let us know some of the main properties of fluids. Properties of fluids are:
1. Density
2. Viscosity
3. Temperature
4. Pressure
5. Specific Volume
6. Specific Weight
7. Specific Gravity
8. Surface Tension
9. Vapors Pressure
10. Capillarity
11. Cavitations

4. Density
Density is defined as the mass per unit
volume of a fluid. The density of a
substance varies as per the volume of a
substance. The SI unit of density is kg.m-3.
Viscosity
Viscosity determines the amount of
resistance offered by the fluid to shear
stress. A fluid that offers no resistance to
shear stress is called an inviscid fluid.

5. Temperature
The degree of hotness or coldness of the
body is determined by the temperature.
The temperature of the fluid is measured
using Kelvin or Celsius or Fahrenheit.
According to the International System of
Units, the Kelvin scale is used.
Pressure
The pressure of a fluid is the force applied
by it per unit area. Fluid pressure takes
place in two conditions: open condition
and closed condition. The pressure at any
given point of a static fluid is called
hydrostatic pressure.

6. Specific Volume
It is defined as the ratio of the volume
of the material to its mass. Specific
volume is the reciprocal of the density
of the material. Specific volume is
inversely proportional to density.
The SI unit of specific volume is m3.kg-1.
Specific Weight
The specific weight (γ) of a fluid is
defined as the weight per unit volume.
The SI unit of specific weight is N/m3.
Specific weight is related to density as γ
= ρg. The specific weight of fluid varies
with temperature.

7. Specific Gravity
It is the ratio of the specific weight of the
given fluid to the specific weight of standard
fluid. Specific Gravity is also known as
relative density. It is represented by the
letter ‘S’ and has no unit.
Surface Tension
It is the tendency of liquid surfaces to shrink
in minimum surface area. Surface tension is
caused by cohesive forces between the liquid
molecules.
Note: Surface tension is the main reason for
most insects to float on the water despite
being denser than water.

8. Cavitations
The process of cavitations happens when
bubbles or voids form within a fluid. This
process takes place when the pressure
drops instantaneously below the vapors
pressure.
Vapors Pressure
The vapors pressure of a liquid is the
equilibrium pressure of a vapors above its
liquid. The vapors pressure of a liquid
varies with temperature. As the
temperature increases, the vapors
pressure also increases.

9. Thank You