by What is meant by share stress?
-The force required to slide one unit area of a layer of fluid over another layer of fluid.
What is viscosity?
- it is a property of fluid, which resists the movement of one layer of fluid over another layer of fluid.
Give example of viscosity fluids?
- Glycerin – castor oil – tar ---- have high viscosity.
- Water – kerosene – petrol ---- have low viscosity.
What is meant by Newton's low of viscosity?
Ι = µ.du/dy
What are the units of viscosity?
- ( Pascal – second) in the SI system
- (lb.s/ft2) in U.S. Customary system.
- ( centipoises_ CP) in CGC system.
Define kinematic Viscosity of fluid?
- it is the ratio between Dynamic viscosity and density of the fluid?
What are the units of kinematic viscosity?
- SI unit ( m2/s)
- CGS ( centistokes – cS )
- U.S. System ( ft2/s)
What are the types of hydraulic fluids?
- ideal fluid
- real fluid or Practical fluid
- Newtonian fluid
- Non – Newtonian fluid
- Compressible fluid
- Incompressible fluid
What is meant by ideal fluid? Give examples?
- Fluid which have no viscosity and surface tension are known as ideal fluids.
- E.g. water and Air
What is meant by real fluid? Give example?
- fluid which have viscosity and surface tension.
- E.g. honey and molasses
What is meant by Newtonian fluids?
- fluids which obeys Newton law of viscosity
What is meant by Non- Newtonian fluids?
- fluids which does not obey Newton law of viscosity
Give example of Newtonian fluids?
- water
- oil
- gasoline
- alcohol
- kerosene
- benzene
- glycerin
What are the types of Non-Newtonian fluids?
- pseudo plastic ( blood plasma, syrups, inks )
- dilatants ( Starch in water )
- Bingham ( catsup, mustard, toothpaste)
What is meant by Electrorheological fluids ( ER Fluids)
- These are fluids developed to offer unique properties that are controllable, by the application of electric current they are suspension of fine particles starch, polymers & ceramics in anon-conducting oil.
Write Electrorheological fluids composition or components?
- Electrorheological fluids of components such as mineral oil or silicone oil with fine particles of surface, polymers which behaves like a solid when electricity applied.
What is meant by Magnetorheological fluids? Write it's components?
- MR fluids contain suspended particles (fine iron powders) in a base fluid.
- Components such as petroleum oil, silicone oil, or water.
What is the effect of temperature and viscosity of liquid?
- Viscosity decreases as temperature increases in liquids.
What is effect temperature on the viscosity of gases?
- viscosity increases as temperature increases.
What is meant by viscosity index?
- A factor which shows the viscosity of fluids with temperature( VI).
What is the meaning of fluids with high VI?
- Exhibits a small change in viscosity with temperature.
What is meaning of fluids with low VI?
- Exhibits a large change in viscosity with temperature.
What is the purpose to use viscometer or rheometers?
- measure viscosity of fluids
What are the various types of viscometers?
- rotating drum viscometer
- capillary tube viscometer
- falling- ball viscometer
- say-bolt universal viscometer
What is meant by capillary tube viscometer?
- (p1 – p2) pressure difference in capillary tube
- Determine of the pipe
- Viscosity of fluids
- Length of the pipe
