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1. GOVERNMENT ENGINEERING
COLLEGE BHAVNAGAR

2.  Subject : Fluid Mechanics
 Topic : Types of Flows
 Branch : 4th Mechanical
 Prepared By :
 Amit H. Makwana ( 140210119064 )
 Dharmesh D. Baraiya ( 140210119005 )

3. Types of Flows
 Steady and unsteady flow.
 Uniform and non-uniform flow.
 Laminar and turbulent flow.
 Compressible and
incompressible flow.
 Rotational and irrotational flow
 One, two and three-dimensional
flow.

4. Steady and Unsteady Flow :
• The flow in which fluid characteristics like velocity,
pressure, density etc. at a point does not changes with time is
called as steady flow.
• Eg flow of water with constant discharge through a
pipeline is as steady flow.
∂v / ∂t = 0 ∂ρ / ∂t = 0 ∂ρ / ∂t = 0
• The flow in which fluid characteristics like velocity,
pressure, density etc. at a point changes with time is called as
unsteady flow.
• E.g flow of water with varying discharge though a pipe is
as unsteady flow.
∂v / ∂t ≠ 0 ∂ρ / ∂t ≠ 0 ∂ρ / ∂t ≠ 0

5. Uniform and Non-uniform Flow :
• The flow in which velocity at a given time does not change
with respect to space (length of direction of flow is called as
uniform flow.
• E.g flow through a long straight pipe of uniform diameter is
considered as uniform flow.
∂v / ∂s = 0
• The flow in which velocity at a given time changes with
respect to space (length of direction of flow) is called as non-
uniform flow.
• E.g flow through a long pipe with varying cross section is
consider as non-uniform flow.
∂v / ∂s ≠ 0
(a) Uniform velocity (b) Non – uniform velocity

6. Laminar and Turbulent Flow :
• The flow in which the adjacent layer do not cross to
each other and move along the well defined path is
called as laminar flow.
• E.g. flow of blood in small veins, flow of ail in
bearings, flow in porous media, flow of highly.
• The flow in which the adjacent layers cross each
other and do not move along the well define path is
called as turbulent flow.
• E.g. flow through a river or canal, smoke from
chimney, smoke from a cigarette.

7. • If Reynolds’s number is less than 2000,
then the flow is laminar.
• If Reynolds’s number is more than
4000, then the flow is turbulent.
• If Reynolds’s number is between 2000
to 4000, then the flow is transit.

8. Compressible and Incompressible Flow :
• The flow in which the density does not remain
constant for the fluid flow is called as compressible
flow.
• E.g. problems involving flight of rockets,
aircrafts, flow fo air in problems concerned with
tubomachines, compressor blades, flow of gases
through openings like nozzles.
• The flow in which the density is constant for the
fluid flow is called as incompressible flow.
• E.g. problems involving liquids i.e. hydraulics
problems, flow of gases in machines like fans and
blowers.

9. Rotational and Irrigational Flow :
• The flow in which the fluid particle while flowing
along stream lines, also rotate about their own axis is
called as rotational flow.
• E.g. motion of liquid in a rotating cylinder (forced
vortex) as rotational flow.
• The flow in which the fluid particle while flowing
along streamlines, do not rotate about their own axis
is called as irrigational flow.
• E.g. flow of liquid in an emptying wash-basin (free
vortex) as a rotational flow.

10. One, Two and Three-dimensional Flow :
• The flow in which the velocity is the function of time and
one space co-ordinate (x) is called as One-dimensional
flow.
• E.g. flow through the pipe is consider as a one
dimensional flow.
u = f(x), v = 0, w = 0
• The flow in which the velocity is the function of time
and to space co-ordinate (x,y) is called as two-dimensional
flow.

11. • Eg viscous flow between parallel plates of large extent, flow at
the middle part of airplane wing, flow over a long spillway, flow
below long weirs are consider as two-dimensional flow.
u = f1(x,y), v = f2 (x,y), w = 0
• The flow is converging or diverging pipes or open channels are
as three dimensional flow. Flow in a river, flow at a inlet of a nozzle
etc. are the example of three-dimensional flow.
u = f1 (x,y,z), v = f2 (x,y,z), w = f3 (x,y,z) 0