Cheg 355 - Lecture Notes - Aug. 23, 2005
Announcements
- Review sessions will be held on Mondays in 129 Debartolo at 6PM. While these are
optional, it would be a good idea to attend if possible. The first review session
will be class pictures for the faceboard (for those who wish it!) and a discussion
of index notation.
Class notes
Scanned Notes
The main points of the lecture were
- What is Fluid Mechanics?
- What is a fluid?
Goals:
After this class you should be able to:
- Identify properties of fluids.
- Know how to classify simple fluid mechanics problems.
Reading
- The class notes.
- BS&L, chapter 1
Additional Readings:
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.
Demonstration:
In class today we demonstrated one difference between Newtonian and non-
Newtonian fluids, in this case the difference between water and wet sand. In the case of
wet sand, when you shear it (e.g., what happened when you pinched the balloon) the
particles of sand tried to move further apart, sucking the water down the funnel to fill
the voids between the particles. Many materials exhibit non-Newtonian behavior
ranging from simple yield stresses (mayo) to the non-zero normal stress differences 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
observed behaviors.
Homework Exercises (Due Aug. 30, 2005)
problem set 1
solution
David.T.Leighton.1@nd.edu