Fluid flow is related with the fluid kinematics

1. Aldel Education Trust’s
ST. JOHN COLLEGE OF ENGINEERING AND MANAGEMENT, PALGHAR
(ST. JOHN POLYTECHNIC)
DEPARTMENT OF MECHANICAL ENGINEERING
SUB: FLUID MECHANICS AND MACHINERY
TOPIC: TYPE OF FLUID FLOWS
PREPARED BY:-
Prof. Pranit Mehata
Lecturer, SJCEM
7972064172

2. INTRODUCTION
 Whenever a fluid is in motion large number of small fluid particles are grouped together to form
the flowing stream.
The branch of fluid mechanics in which fluid motion is considered is called as fluid kinematics.
Flow of fluid may occurs due to
i. Difference of energy between one point to second point
ii. Pressure difference
iii. Difference in datum energy.

3. TYPES OF FLUID FLOWS

4. STEADY AND UNSTEDAY FLOW
Steady flow : The type of flow in which the fluid characteristics like
velocity, pressure, density, etc. at a point do not change with time.
Mathematically,
𝜹𝑽
𝜹𝒕
= 𝟎,
𝜹𝑷
𝜹𝒕
= 𝟎,
𝜹𝝆
𝜹𝒕
= 𝟎
e.g. flow of water through a tap at a constant rate
Unsteady flow: It is that type of flow in which the velocity, pressure or
density at a point change w. r .t. time.
Mathematically,
𝜹𝑽
𝜹𝒕
≠ 𝟎,
𝜹𝑷
𝜹𝒕
≠ 𝟎,
𝜹𝝆
𝜹𝒕
≠ 𝟎
e.g. flow of water through tap when tap is just made open

5. UNIFORM AND NON-UNIFORM FLOW
Uniform flow : The type of flow, in which the velocity at any given time does not
change with respect to space.
Mathematically,
𝜹𝑽
𝜹𝒔
= 𝟎
e.g. flow of water through a long pipe of uniform (same) diameter.
Non-uniform flow : The type of flow, in which the velocity at any given time
changes with respect to space.
Mathematically,
𝜹𝑽
𝜹𝒔
≠ 𝟎
e.g. flow of water through a long pipe of varying cross section

6. COMPRESSIBLE AND INCOMPRESSIBLE FLOW
Compressible flow : It is that type of flow in which the density (ρ)
of the fluid changes from point to point.
Mathematically, 𝝆 ≠ 𝒄𝒐𝒏𝒔𝒕𝒂𝒏𝒕
e.g. all gases
Incompressible flow : It is that type of flow in which density is constant
for the fluid flow..
Mathematically,𝝆 = 𝒄𝒐𝒏𝒔𝒕𝒂𝒏𝒕
e.g. all liquids

7. ROTATIONALAND IRROTATIONAL FLOW
Rotational flow : A flow is said to be rotational if the fluid particles
while moving in the direction of flow rotate about their own axis
e.g. Motion of liquid in a rotating tank.
Irrotational flow : A flow is said to be irrotational if the fluid particles
while moving in the direction of flow do not rotate about their own axis.
e.g. Flow above a drain hole of a stationary tank or a wash basin.

8. LAMINAR AND TURBULENT FLOW
Laminar Flow : A laminar flow is one in which paths taken by the
individual particles do not cross one another and move along well defined
paths. For laminar flow Reynolds number (Re) < 2000
e.g. flow of blood in veins , ground water flow
Turbulent Flow : A turbulent flow is that flow in which fluid particles move in
a zig zag way. For turbulent flow Reynolds number (Re) > 4000
e.g. flow of water from river at a time of flood.

9. ONE, TWO AND THREE DIMENSIONA FLOW
One dimensional Flow : It is that type of flow in which
the flow parameter such as velocity is function of time
and one space co-ordinate only. e.g. Flow in a pipe where
average flow parameters are considered for analysis
Mathematically, 𝒖 = 𝒇 𝒙 , 𝒗 = 𝟎, 𝒘 = 𝟎
Two dimensional flow: The flow in which the velocity is
function of time and two space co-ordinates. e.g. flow
between parallel plates
Mathematically, 𝒖 = 𝒇𝟏 𝒙, 𝒚 , 𝒗 = 𝒇𝟐 𝒙, 𝒚 , 𝒘 = 𝟎
Three dimensional flow: The flow in which the velocity is
function of time and three mutually perpendicular directions.
e.g. flow in converging or diverging pipe.
Mathematically, 𝒖 = 𝒇𝟏 𝒙, 𝒚, 𝒛 , 𝒗 = 𝒇𝟐 𝒙, 𝒚, 𝒛 , 𝒘 =
𝒇𝟑 𝒙, 𝒚, 𝒛 ,
One
dimensional
flow
Two
dimensional
flow
Three
dimensional
flow