Viscosity of fluids

Remark……………………. Page 1
DAYANAND DINANATH
EDUCATION CENTRE
RAMAIPUR KANPUR NAGAR
PHYSICS INVESTIGATORY PROJECT
SUBMITTED TO – SUBMITTED BY -
MR. SHUBHAM XYZ
GUPTA

CERTIFICATE
This is to certify that (student
name) is a student of class XI has
successfully completed the research
on the below mentioned project
under the guidance of Mr.
SHUBHAM GUPTA ( subject
teacher) during year 2020-2021 in
partial fulfillment of physics practical
examination of Central Board Of
Secondary Education (CBSE)
PRINCIPAL SUBJECT TEACHER
Mrs. SHIPRA MR. SHUBHAM
BHATIA GUPTA

DECLARATION
I hereby declare that the project
work entitled “ VISCOSITY OF
FLUIDS ” submitted to
“DAYANAND DINATH EDUCATION
CENTRE SCHOOL ” is a record of
original work done by me except
of the experiments which are truly
acknowledged , under the guidance
of my Subject Teacher “ Mr.
SHUBHAM GUPTA ” .

ACKNOWLEDGEMENT
I would like to express my
gratitude to my teacher MR.
SHUBHAM GUPTA , as well as
our principal Mrs. SHIPRA
BHATIA who gave me the
opportunity to do this
wonderful project on the topic
VISCOSITY OF FLUIDS. The
project helped me learn how to
do proper Research and I
learned about many new things
while doing the project.
I would also like to thank my
parents and friends who
helped me complete this project
within the deadline.

INDEX
1. Importance of viscosity.
2. Intro…. of viscosity.
3. Examples of viscosity.
4. Viscosity formula.
5. Unit of viscosity
6. Why should you measure viscosity
7. Type of viscosity
8. Coefficient of viscosity.
9. Fluid friction
10. Fluid flow
11. Bibliography

Importance of viscosity.
What happens when you pour 500 ml
of water on someone’s head (apart
from them getting angry). It runs
through their hair and flow over their
face. But what happens when you
pour 500 ml of honey on someone’s
head? It takes its own sweet time in
running its’ course through that
person’s head, doesn’t it? Why the
difference? This is because of a
property of fluids called VISCOSITY

WHAT IS VISCOSITY?
Viscosity is defined as the measure of
the resistance of a fluid to gradual
deformation by shear or tensile stress.
In other words, viscosity described a
fluid’s resistance to flow. Simply put we
can say that honey is thicker than
water; In turn honey is more viscous
than water.
 The viscosity of a fluid is a
measure of its resistance to
deformation at a given range

Examples of viscous substance
 OIL
 Honey
Dental Paste
Hair gel
Glycerin
Ethyl alcohol
Bitumen
Syrups
Brea
Mercury
Engine oil

VISCOSITY FORMULA
Viscosity is measure in terms of a ratio of
shearing stress to the velocity gradient In a
fluid . if a sphere is dropped into a fluid , the
viscosity can be determine using the
following formula .
“η=2ga*2(Δρ)/9v
Viscosity of Common liquids–
Liquid Viscosity
[Ns/m*2]
Gasoline 600
Water 1000
Milk 1200
Bear 1800
Motor oil 500,000
Honey 10,000,000
Peanut butter 250,000,000
Olive oil 40,000
ketchup 50,000,000

Unit of viscosity
SI Unit = Pascal seconds (pa* s)
or Kg/ms
CGS Unit = Poise(p)
Other Viscosity Units
Saybolt Universal Seconds (or SUS,
SSU)
SSU is a dated unit of measure of
viscosity originating in the oil and
petroleum industries.
SSF
(Saybolt Seconds Furol)

Viscosity is measured in
Pascal seconds (pa s).
example
Viscosity of water is 0.001 (pa s), that of air is 0.000019 (pa s) and
that of motor oil is 1. So you can pretty much do the math here.
Also, the viscosity of liquids decreases as the temperature
increases, while for gases, it increases with the increase in
temperature
Do you know?
The dynamic viscosity of water at room
temperature 25ºC are having various values
mentioned below:
1. In the SI unit , the value of viscosity is 8.90 x
10^-4 Pa*s
2. In CGS unit, the value of viscosity is 8.90 x
10^-3 dyne*s/cm^2 or 0.890 cP
Therefore, water has a viscosity of 0.0091 poise
 Viscosity and density are 2 different terms where
viscosity is the thickness of fluid and density refers
to the space between its particle

WHY SHOULD YOU
MEASURE VISCOSITY?
Gathering the data of the viscosity of
a given material helps manufactures
predict how the material behaves in
the real world.
For example - if the toothpaste does not have the
correct viscosity, it will either be too difficult to pump
out the paste from the tube or too much of it will be
pumped out.

TYPES OF VISCOSITY
As we know, the viscosity is the measure of the
friction of fluids. There are 2 ways to measure
a fluid’s viscosity as follows:
 Dynamic Viscosity (Absolute
Viscosity)
 Kinematic Viscosity
DYNAMIC VISCOSITY
Dynamic viscosity is the force needed by
a fluid to overcome its own internal
molecular friction so that the fluid will
flow.
Dynamic viscosity is defined as the tangential
force per unit area needed to move the fluid in
one horizontal plane with respect to other
plane with a unit velocity while the fluid’s
molecules maintain a unit distance apart.

Shear stress can be expressed
τ = μ dc / dy
= μ γ

Liquid
Absolute Viscosity *)
(N s/m2
, Pa s)
Air 1.983 10-5
Water 10-3
Olive Oil 10-1
Glycerol 100
Liquid Honey 101
Golden Syrup 102
FLUID DYNAMIC
VISCOSITY
KINEMATIC
VISCOSITY
TEMPERA
TURE
Name [cP] [cSt] [ºC]
Water 1 1 20
Air 0.018 13.9 27
Honey 5000 3500 25
Mercury 1.526 0.11 25
Ethanol 1.074 1.36 25

KINEMATIC VISCOSITY
Kinematic viscosity is the sort of
viscosity that is computed by
calculating the ratio of the fluid mass
density to the dynamic fluid,
viscosity or absolute fluid viscosity.
It is from time to time also known as
momentum diffusivity.
The units of kinematic viscosity are
established on time and area of fluid.
Kinematic viscosity can be
computed by dividing the absolute
viscosity of a fluid with the fluidb
mass density.

FORMULA OF KINEMATICS VISCOSITY
KINEMATICS VISCOSITY = Dynamic
viscosity/Fluid Mass Density
MATHEMATICALLY, V = µ/rho

COEFFICIENT OF VISCOSITY
Coefficient of viscosity is defined as the ratio of
the force required to make adjacent layers of
the liquid move over each other.
The ratio of the shearing stress to the velocity
gradient of the fluids is called the coefficient of
viscosity ղ.
Hence the coefficient of viscosity is given by.
ղ = F.d/A.v
Where
F is the tangential force required to maintain a
unit velocity gradient between two parallel layers of
liquid of unit area.
v is the velocity.
A is the area.
d is the distance between the two layers of liquid
skidding over each other.
the viscosity of gas is less than the liquid viscosity.

SI unit of Coefficient of viscosity
Every liquid has its own specific viscosity
and the measure of this attribute is called
the coefficient of viscosity.
The SI unit of ղ is Newton-second per
square meter (Ns.m^-2) or Pascal-
seconds(Pa.s)
Coefficient of viscosity unit and
Dimension
Since, the formula for coefficient of viscosity is given by.
ղ = F.d/A.v = [MLT^-2].[L]/[L^2].[LT^-1]
On solving we get –
Dimensional formula for ղ =
[ML^-1T^-1]

FLUID FRICTION
Friction is the force resisting the relative motion of solid
surfaces, fluid layers, and material elements sliding
against each other.
WHAT IS FLUID FRICTION?
Fluid friction occurs between fluid layers
that are moving relative to each other.
This internal resistance to flow is named
viscosity. In every day terms, the
viscosity of fluids described as its
“thickness”
All real fluids offer some resistance to
shearing and therefore are viscous. It is
helpful to use the concept of an inviscid
fluid or an ideal fluid that offers no
resistance to shearing and so is not
viscous.

Several type of friction
 Dry Friction resists the relative
lateral motion of two solid surfaces in
contact.
 Fluid Friction describes the friction
between layers of a viscous fluid that are
moving relative to each other.
 Lubricated friction is a case of
fluid friction where a lubricant fluid
separates two solid surfaces.
 Skin Friction is a component of
drag, the force resisting the motion of fluid
across the surface of the body.
 Internal Friction is the force
resisting motion between the elements
making up a solid material while it
undergoes deformation.

Examples of fluid friction
 If there is a wet surface between two thin
glass plates, you will notice that plates get
stuck and the bottom plate doesn’t fall when
you hold only the top one
 When any object is dropped in a fluid, extent
of the splash is dependent on the fluid friction
of that particular fluid.
 You find lighter dust particles move fast on
the surface of a flowing river. This is due to
the high -velocity gradient at the top layer of
water due to lower dynamic fluid friction at
that layer.

FLUID FLOW
Fluid Flow is a part of fluid mechanics and
deals with fluid dynamics. It involves the
motion of a fluid subjected to unbalanced
forces. This motion continues as long as
unbalanced forces are applied.
For example, if you are pouring water from mug,
the velocity of a water is very high over a lip,
moderately high approaching the lip, and very
low at the bottom of the mug.

The unbalanced force is gravity, and flow is
continues as long as the water is available and
the mug is titled.

Types of fluids
Ideal fluid = A fluid is said to be a ideal when it
cannot be compressed and the viscosity does not fall in
the category of ideal fluid. It is an imaginary fluid which
doesn’t exist in reality.
Real fluid = all the fluids are real as the fluid
possess viscosity.
Newtonian fluid = when the fluid obeys the
Newton’s law of viscosity.
Non-Newtonian fluid = doesn’t obey Newton’s law of
viscosity
Ideal plastic fluid = when the shear stress is
proportional to the velocity gradient and shear stress is
more than the yield value.
Incompressible fluid = when the density of fluid
doesn’t change with the application of external force.

Compressible fluid = when the density of fluid
changes with the application of external force.
TYPES OF
FLUID
Density Viscosity
Ideal fluid Constant Zero
Real fluid Variable Non-Zero
Newtonian fluid Constant/
Variable
T = u(du/dy)
Non – Newtonian fluid Constant/
Variable
T ≠
u(du/dy)
Incompressible fluid Constant Non-
Zero/zero
Compressible fluid Variable Non-
Zero/zero
Classification of flows on the basis of
mach number
 Incompressible flow has M<0.3
 Compressible subsonic flow has M between 0.3 - 1

Types of fluid flow
Fluid flow has all kinds of aspects – steady or
unsteady, compressible or incompressible,
viscous or non viscous, and rotational or
irrotational, to name a few. Some of these
characteristics reflect the properties of the
liquid itself, and other focus on how the fluid
is moving.
Steady or Unsteady Flow (depending
on fluids velocity)
 STEADY: velocity of fluid is
constant
 UNJSTEADY: velocity can differ
between any two points.

Viscous or Non Viscous flow
Viscosity is a measure of the thickness of a
fluid, and very gloppy fluids such as motor oil or
shampoo are called viscous fluids.
FLUID FLOW EQUATION
Mass flow rate is the rate of movement of a
massive fluid through a unit area. In simple words it
is the movement of mass per unit time. The formula
for mass flow rate is given as follows:
Mass flow rate = ρAV

Fluid flow through a pipe
The general capacity of the pipes varies on its size.
The table given below shows the capacity of the flow
of fluid based on its size
Pipe
size(inch)
Maximum
flow(gal/min)
Velocity(ft/s)
2. 45 4.3
2.5 75 5.0
3 130 5.6
4 260 6.6
6 800 8.9
8 1600 10.3
10 3000 12.2
12 4700 13.4
14 6000 14.2
16 8000 14.5
18 10000 14.3
20 12000 13.8
24 18000 14.4

BIBLIOGRAPHY
Help from internet
www.byjus.com
www.vedantu.com
Google photos
Help from book
 HC VERMA physics
class 11 part 1

Viscosity of fluids

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Viscosity of fluids

Similar to Viscosity of fluids (20)

Recently uploaded

Recently uploaded (20)

Viscosity of fluids