# Thermofluids L1 Flashcards

1
Q

What are FLUID MECHANICS?

A

The branch of physics that studies the mechanics of fluids (liquids, gases and plasma) and the forces on them.

2
Q

What is a FLUID?

A
• A fluid is a substance that continually deforms (flows) under an applied shear stress
• It has no fixed shape and yields to
pressure
3
Q

What can fluids include?

A

liquids, gases, plasmas and, to some extent, plastic solids

4
Q

What is Relative Density?

A

The ratio of the density of a substance to the density of a given reference material

5
Q

What is a Specific Volume?

A

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

6
Q

Why is volume is an extensive property?

A

Volume is an extensive property as it is dependent upon the size of a
system

7
Q

Why is Specific volume is an intensive property?

A

Classed as an intensive property as it is independent of system size

8
Q

What is the equation for Specific Volume?

A

V = v / m = 1 / p

9
Q

What is Pressure (Pa)?

A

The force applied perpendicular to the surface of an object per unit area over which that force is distributed

10
Q

What is absolute pressure?

A
• 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
11
Q

What is Gauge pressure?

A
• 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
12
Q

What is the difference between Gauge and Absolute Pressure?

A
• 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
13
Q

What is the equation for Pressure above P(atm)?

A

P(gauge) = P(abs) - P(atm)

14
Q

What is the equation for Pressure below P(atm)?

A

P(vac) = P(atm) - P(abs)

15
Q

What is the relationship between Pressure and Depth?

A

As the Depth increases the Pressure increases as fluid layers rest on other fluid layers