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CHAPTER 1

FLUIDCHARACTERISTICS

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FLUID MECHANICS

The study of liquidand gasesat rest (statics) and

motion (dynamics)

fluids (liquid and gases)a substance which

deforms continuously, or flows when subjected toshear stress

Engineering applications

Dams and reservoirs

Water supply pipelines

Groundwater movement

Pumps, filters, rivers

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Physical characteristic of fluid

Both liquid and gases are classified as fluid

Fluids do not resist a change in shape.

It assume the shape of container they occupy

Fixed volume Liquids are almost incompressible

Gases are easily compressed- fill a container they occupy

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Density,

Mass of substance per unit volume (kg/3)

Density, =

=

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Specific Weight or Weight Density,

The force exerted by the earths gravity up on a unit

volume of substance

Specific Weight,=

= =

=

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Specific gravity (relative density), s

The ratio of the fluid density to the weight density of a

standard fluid

Specific Gravity, s (for liquid) =

=

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Specific volume, Vs

The volume of fluid occupied by a unit mass or volume

per unit mass of a fluid

Specific Volume, Vs =

=

= 1

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Example1. Calculate the specific weight, density and specific gravity of

one litre of a liquid which weight 7 N.

2. A container of volume 3.0 m3has 25.5 kN of an oil.Calculate specific weight, density and specific gravity.

3. Calculate density, specific weight, and weight of one litre ofpetrol of specific gravity = 0.7

4.One litre of crude oil weight 15.5 N. calculate its specificweight, density, specific gravity and specific volume

5. Mass of a liquid is 5655 g and 3300 litre respectively.Determine weight, density, and specific weight for the liquid.