What are FLUID MECHANICS?
The branch of physics that studies the mechanics of fluids (liquids, gases and plasma) and the forces on them.
What is a FLUID?
- A fluid is a substance that continually deforms (flows) under an applied shear stress
- It has no fixed shape and yields to
pressure
What can fluids include?
liquids, gases, plasmas and, to some extent, plastic solids
What is Relative Density?
The ratio of the density of a substance to the density of a given reference material
What is a Specific Volume?
The specific volume of a substance is the ratio of the substance’s volume to its mass.
It is the reciprocal of density and an intrinsic property of matter as well
Why is volume is an extensive property?
Volume is an extensive property as it is dependent upon the size of a
system
Why is Specific volume is an intensive property?
Classed as an intensive property as it is independent of system size
What is the equation for Specific Volume?
V = v / m = 1 / p
What is Pressure (Pa)?
The force applied perpendicular to the surface of an object per unit area over which that force is distributed
What is absolute pressure?
- The pressure of having no matter inside a space, or a perfect vacuum.
- Measurements taken in absolute pressure use this absolute zero as their reference point
What is Gauge pressure?
- Gauge pressure is measured in relation to ambient atmospheric pressure
- A gauge pressure higher than ambient pressure is referred to as positive pressure
- If the measured pressure is below atmospheric pressure it is called negative or vacuum gauge pressure
What is the difference between Gauge and Absolute Pressure?
- Absolute pressure uses absolute zero as its zero point, while gauge pressure uses atmospheric pressure as its zero point
- Due to varying atmospheric pressure, gauge pressure measurement is not precise, while absolute pressure is always definite
What is the equation for Pressure above P(atm)?
P(gauge) = P(abs) - P(atm)
What is the equation for Pressure below P(atm)?
P(vac) = P(atm) - P(abs)
What is the relationship between Pressure and Depth?
As the Depth increases the Pressure increases as fluid layers rest on other fluid layers
