The document discusses viscosity measurement and various types of viscometers, including U-tube and falling-sphere viscometers. It explains the concept of viscosity, its significance in fluids, and specifically blood viscosity, and factors affecting it such as plasma viscosity and red blood cell behavior. The importance of using viscometers to measure viscosity in controlled conditions is also highlighted.

1. Viscometer
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2. Topic to Duscussed
Viscosity
Measuement
Viscometer
Types
U-Tube Viscometer
Falling Sphere Viscometer
Blood Viscosity
Conditions
Factors affecting Blood Viscosity
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3. Viscosity
Jean-Louis-Marie Poiseuille was a
French physicist and physiologist
whose interest in the circulation of
blood in the human body led him
to discover viscosity

4. What is
Viscosity?
The viscosity of a fluid is a
measure of its resistance to
deformation at a given rate.
For liquids, it corresponds to the
informal concept of "thickness":
for example, syrup has a higher
viscosity than water.

5. Dynamic viscosity, also
known as absolute viscosity
Kinematic viscosity
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There are two
types of
viscosity
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6. It is the tangential force per
unit area required to move one
horizontal plane with respect
to another horizontal plane at
a unit velocity when
maintained a unit distance
apart by the fluid.
Dynamic
viscosity
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7. Dynamic viscosity
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8. Kinematic viscosity is a measure of a fluid's internal
resistance to flow under gravitational forces. It is
determined by measuring the time in seconds,
required for a fixed volume of fluid to flow a known
distance by gravity through a capillary within a
calibrated viscometer at a closely controlled
temperature.
Kinematic viscosity
Kinematic viscosity is the ratio of dynamic viscosity to
density.Learn More About Viscosity

9. Kinematic viscosity = Dynamic viscosity / Fluid mass density.
Kinematic viscosity

10. Viscometer
A viscometer (also called viscosimeter) is an instrument used to
measure the viscosity of a fluid. For liquids with viscosities which vary
with flow conditions, an instrument called a rheometer is used.

11. Types of
Viscometers
U-tube viscometers
Falling-sphere viscometers
Falling-ball viscometer
Falling-piston viscometer
Oscillating-piston viscometer
Vibrational viscometers
Rotational viscometers
Bubble viscometer
Rectangular-slit viscometer
Krebs Viscometer
Miscellaneous viscometer types

12. U-tube viscometers
It consists of a U-shaped
glass tube held vertically in a
controlled temperature bath.
In one arm of the U is a
vertical section of precise
narrow bore (the capillary).
Above there is a bulb, with it
is another bulb lower down
on the other arm.

13. U-tube viscometers
The time required for the test
liquid to flow through a
capillary of a known diameter
of a certain factor between
two marked points is
measured
By multiplying the time taken
by the factor of the
viscometer, the kinematic
viscosity is obtained.

14. Falling-sphere viscometers
Stokes' law is the basis of the falling-
sphere viscometer, in which the fluid is
stationary in a vertical glass tube
A sphere of known size and density is
allowed to descend through the liquid
If correctly selected, it
reaches terminal velocity, which can
be measured by the time it takes to
pass two marks on the tube.

15. Falling-sphere viscometers
Stokes' law can be used to calculate
the viscosity of the fluid
Navier–Stokes equations:

16. Blood Viscosity
Blood viscosity is a measurement of the thickness and
stickiness of an individual's blood. It is a direct
measure of the ability of blood to flow through
the blood vessels.

17. Blood
viscosity
affect blood
flow
Increased viscosity increases
the resistance to blood
flow and thereby increases
the work of the heart and
impairs organ perfusion
Some patients with anemia
have low hematocrits, and
therefore
reduced blood viscosities.
Another important factor that
influences blood viscosity is
temperature.

18. Factors affect
blood
viscosity
Plasma viscosity
Red blood cell (RBC)
deformability and
aggregation
Depending on the vascular
compartment and the flow
conditions
Blood viscosity is influenced by
several other
hemorheological/hematological
parameters such as

19. Good luck!