Preface_1995_Modeling-Axisymmetric-Flows

Prévia do material em texto

Preface 
One afternoon, while trying to find some logic in my professional life, I came 
to the realization that much of my research efforts had centered around the fluid 
dynamics of what seemed to be a very restricted class of flows: low Reynolds 
number flows into, through, and from a capillary tube, and the creation and sub- 
sequent behavior of drops formed from capillaries. Was this, I wondered, the 
result of some dementia? Had a childhood trauma led me inexorably along this 
path? Or could one argue, instead, that such flows are interesting from both a 
fundamental and a practical perspective? 
This "slim volume" is an attempt to demonstrate that one can teach an interest- 
ing and enjoyable second course in fluid dynamics aroundmby and largem 
axisymmetric flows from capillaries, and the dynamics of drops and bubbles and 
films. In the end, very little of my own work appears, testimony to the reality that 
so much more and better has been done on these flows since I began my studies 
in the laboratory of Jerry Gavis, in the moist and reverberant basement of 
Maryland Hall at The Johns Hopkins University. At The Hopkins I had the great 
privilege of studying fluid dynamics in the classrooms of Stanley Corrsin and 
Owen Phillips. In the laboratory, Gavis was a wise mentor, letting me follow my 
intuition as I tried to find something interesting to make into a dissertation. An 
indispensable addendum to my education came from the happy fact that I shared 
the laboratory (and, one summer, digs on the Left Bank of the Raritan River) with 
my friend and classmate Simon Goren. Simon painted honey onto wires, I squirt- 
ed liquids out of long tubes, and we both tried, with very little success, to explain 
to our friends and relatives what it was we were doing, and harder yet, why. 
There is a richness in the topics of this small book that transcends the space 
they occupy. This is especially true of free boundary problems, where surface 
tension plays an essential role in the dynamics. Most classic texts in fluid 
dynamics~and, sadly then, most coursesmfail to give attention to this class of 
xiii 
xiv Preface 
flow. Hence one of my goals is to provide a vehicle for the continuing education 
of the student of fluid dynamics into the realm of free boundary flows. Another 
is to demonstrate the art of mathematical modelingmthe iterative building of a 
theory, or at least a predictive model, from knowledge, intuition, and observa- 
tion. Hence I try to provide throughout the book an abundant variety of exam- 
ples of comparisons of experimental data with models of the flows described. In 
some cases this has necessitated that I convince a student to disappear into my 
own laboratories, therein to generate the required evidence, pro or con, of the 
utility of some simple mathematical model of a complex flow. In the end, this is 
the goal: to make the complex simple, without losing the essencemthe vir tue~ 
of the complexity. 
Stanley Middleman