Stefan LLEWELLYN SMITH
EBUII 574
x23475
http://mae.ucsd.edu/~sgls
Homework I
Due
Friday January 17, 2020, in class (or before).
Problems (MYO is the textbook, 8th edition)
MYO 1.73
MYO 2.54
MYO 3.74
MYO 4.55
MYO 5.63
MYO 6.94
Fluid mechanics provides the opportunity for beautiful
visualizations. Find a striking image or video on the Internet
and write a paragraph about it, including the origin of the
image or video, why it was made, its scientific or technological
relevance, and why you think it is interesting and/or beautiful
and/or educational. One good resource is the Gallery of Fluid Motion, but
Google Search will provide many other examples. There are no
right or wrong answers to this question. However, you should aim
to write a coherent paragraph. I will read these, and then
rather than assign points for this question, I'll include a
-/0/+ note for my records that could come into play during
borderline decisions about final grades. This is a chance for
you to express yourselves and develop a personal connection with
fluids. (A colleague in Visual Arts provided the following link: labocine.com, which appears to
include short scientific/arts films. Some might involve fluids.)
Comments
We have been reviewing a quarter's worth of fluid mechanics in 5
lectures or so, so there hasn't been time to cover everything. The
book's treatment is good, but the chapters are fairly long, so I
would recommend you try and focus on which equations or discussions
are most important. One good approach is to work back from the
Chapter Summaries and Study Guides. Topics that will be particularly
relevant for the new material in this class are Bernoulli's
equation, particularly Sections 3.5–3.7, control volume analysis for
the momentum and energy equations (Sections 5.2 and 5.3), Poiseuille
flow (Section 6.9) and Dimensional analysis (in particular Sections
7.2, 7.6 and 7.7). In the homework I have assigned one
representative question from each chapter up to Chapter 6. Usually
there will be 8 questions; this week there are 7.
The last question in each homework is a chance for you to learn
something about fluid mechanics beyond the lectures and textbook.
Please use appropriate citations. Last time, students were not going
a good job with this and were essentially plagiarizing, so we ended
up using turnitin.com, which was a hassle for everyone.
We will next start to look at viscous flow through pipes (Chapter 8
of the book). You have already encountered laminar flow in pipes:
this is Poiseuille (or Hagen–Poiseuille) flow. However, if the
Reynolds number is large enough, the flow may be turbulent. The
instantaneous prediction of turbulent flow is usually a futile task.
What we want is to understand the relation between the properties of
the pipe and fluid (diameter, length, viscosity), the pressure drop
and the flow rate. Even though the flow is turbulent, there is a
well-defined relation between these if we consider mean
quantities.
We will first look at the general characteristics of pipe flow
(Section 8.1). This might be a good time to review the Reynolds pipe
experiment: there are plenty of YouTube videos that feature it, with
diverse soundtracks. Then we will review laminar flow (Section 8.2),
and examine the corresponding force and energy balance.