PRELIM Flashcards
are substances capable of flowing, heaving particles which easily move and change their relative position without separation of mass.
Fluids
Fluids readily conform to the shape of the _____ _____ with which they come into contact
solid body
Fluids may be divided into ______ and ______
liquids and gases
Liquids have free surface while gas does not.
What is a free surface
It is a surface or the uppermost part of a liquid in contact with earth’s atmosphere (air).
Mass of liquid and gas in connection to volume
liquid occupies only given volume while gas occupies all portions of any container regardless of its size
Liquids are practically incompressible while gases are compressible, what does it mean
incompressible means it does not expand, does volume is constant.
what happens to gas and liquid in a closed container
to ensure equilibrium, liquid produces vapor in a closed container
gas, on the other hand, produces more pressure in closed container if increases
Mass Density (ρ) formula
ρ = m / v
kg/m³
ρ
rho
Mass Density
mass per unit volume
mass density
the gravitational force per unit volume of fluid.
The weight of a unit volume of a fluid
Unit Weight or Specific Weight (γ)
γ
gamma
Unit Weight or Specific Weight
Unit Weight or Specific Weight (γ) formula
γ = w / v
γ = ρg
N/m³ or kN/m³
is the volume occupied by a unit mass of fluid
Specific Volume
Vs
Specific Volume
Specific Volume (Vs) formula
Vs = 1/ρ
m³ / kg
is the dimensionless ratio of a fluid density to a standard reference density.
Specific gravity
s
Specific Gravity
Specific gravity (s) formula
s = ρ ʟɪǫᴜɪᴅ / ρ ʜ2ᴏ @ 4°C
s = ρ ɢᴀs / ρ ᴀɪʀ
Weight formula
w = mg
N or kN
Mass density of water at 4°C
ρ = 1,000 kg/m³
Unit or Specific weight of water at 4°C
γ = 9,810 N/m³
Specific gravity of water at 4°C
s = 1.0
Mass density of air
ρ = 1.23 kg/m³
Unit or Specific weight of
γ = 12.1 N/m³
Specific gravity of air
s = 0.00123
Internal stickiness of a fluid
Viscosity (μ) (mu)
Property of fluid which determines the amount of its resistance to shearing force.
Viscosity (μ) (mu)
One of the properties of fluid that controls the amount of fluid that can be transported in a pipeline during a specific period of time.
Viscosity (μ) (mu)
a device that measures the viscosity of a fluid
Viscometer
Relationship between liquid viscosity and temperature
Indirectly proportional
viscosity of liquid decreases with increasing temperature
Relationship between gas viscosity and temperature
Directly proportional
gas viscosity increases with increasing temperature
What are the general properties of fluids
- Mass density (ρ)
- Unit or Specific Weight (γ)
- Specific Volume (Vs)
- Specific Gravity (s)
- Viscosity (μ)
- Surface tension (σ)
- Vapor Pressure
- Capillary Action
It is the property of fluid that results from the attractive forces between molecules
Surface tension (σ)
It manifests itself only in liquids at an interface, usually a liquid-gas interface
Surface tension (σ)
Relationship between surface tension and temperature
Indirectly proportional
Surface tension of liquid decreases as their temperature rises
Is explained by the phenomenon of surface tension combined with that of adhesion
Capillary Action
Relationship between effect of capillary and size of tube
Indirectly proportional
The effect of capillary decreases as the size of the tube increases
The pressure resulting from molecules in the gaseous state.
Vapor pressure
It is the pressure of which the liquid will boil
Vapor Pressure
μ
Viscosity
σ
Surface tension
