CBE 30355 - Lecture Notes - Aug. 23, 2022
Read through pages 1-16 of the notes and view the online narration below. Don't forget to complete the quiz in Canvas!
The main points of the lecture were
- What are Fluid Mechanics?
- What is a fluid?
After this class you should be able to:
- Identify properties of fluids.
- Know how to classify simple fluid mechanics problems.
- The class notes.
- BS&L, chapter 1
In class today we discussed fluid properties such as viscosity and density. It's a
good idea to have a 'gut' knowledge of the magnitude of these quantities so you
have a better chance of knowing when your calculations are off - a sort of "Wait a
minute, that doesn't make any sense" ability. For a classic example of what can happen
if you - don't - I offer you the Gimli Glider, described here.
In class today we demonstrated one difference between Newtonian and non-
Newtonian fluids, in this case the difference between a pure Newtonian fluid
and a suspension of sand (glass spheres). As the suspension is squeezed out
between the plates particles accumulate at the advancing meniscus, causing a
classic viscous fingering instability. The migration occurred because the
particles "push" each other apart as a suspension is sheared between the plates.
These sorts of phenomena are important
in multiphase flows used in such disparate areas as oil recovery and medical
diagnostic chips. Papers describing this and related phenomena may be found
Many materials exhibit non-Newtonian behavior
ranging from simple yield stresses (mayo) to the non-zero normal stresses of
the concentrated suspension in this example. We'll mainly focus on Newtonian fluids
this term due to their simplicity and importance (e.g., water is all around us!) but you
should also be aware that it is a special (albeit pretty common) case of a larger range of