HYDRAULICS - Properties of Fluids and Unit Pressures

Fluid

A substance that cannot remain at rest under action of any shear force

Liquid and Gas

Fluid pertains to ______ and _______

4°C

Density of water is maximum at ____

Cohesion

Property of a fluid by which its own molecules are attracted

Adhesion

Property of fluid by which molecules of different kinds of fluids are attracted to each other

At rest

The normal stress in a fluid will be constant in all directions at a point only if it is _______

more

Specific weight of sea water is ______ that of pure water because it contains dissolved air, dissolved salt, and suspended matter

Surface tension

Free surface of a liquid tends to contract to the smallest possible area due to force of _______

More than

A liquid would wet the solid if the adhesion forces is ___________ cohesion forces.

Barometer

Used to measure the atmospheric pressure

Manometer

Used to measure pressure in pipes, channels, etc.

Lower

If cohesion between molecules of a fluid is greater than adhesion between fluid and glass, then the free level of fluid in a dipped glass tube will be ________ than the surface of liquid

Compressibility

Causes the volumetric change when a fluid is subjected to resistance

Pascal’s Law

States that liquid transmit pressure equally in all directions

Decrease

The rise or depression of liquid in a tube due to surface tension with an increase in size of tube will ______

Mercury

Often used in barometer because the height of the barometer will be less and it’s vapor pressure is so low that it may be neglected

Weight

Also called as gravity force

kg/m³

Unit of mass density

kN/m³ or force/volume

Unit of specific weight

Specific weight

Weight over volume

Specific weight

Density times gravity

Specific weight

Specific gravity x gamma of water (Yw)

23

Conversion of Celsius to Kelvin

°C + ___