Page 19 - Introduction to Computational Fluid Dynamics

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PREFACE
internal heat generation, and with linear or nonlinear boundary conditions) in a
typical undergraduate textbook can be solved by a single computer program based
on a single method is found by the students to be new. Similarly, the idea that
a numerical instability in an unsteady conduction problem essentially represents
violation of the second law of thermodynamics is found to be new because no book
on numerical analysis treats it as such. Nothing encourages a teacher to write a book
more than the discomfort expressed by the students. At the same time, it must be
mentioned that when a student succeeds in writing a generalised computer program
for 1D conduction in the laboratory part of the course through struggles of where
and how do I begin, of debugging, of comparing numerical results with analytical
results, of studying effects of parametric variations, and of plotting of results, the
computational activity is found to be both enlightening and entertaining.
I specifically mention these observations because, although there are a number
of books bearing the words Computational Fluid Dynamics in their titles, most em-
phasise numerical analysis (a branch of applied mathematics). Also, most books, it
would appear, are written for researchers and cover a rather extended ground but are
usually devoid of exercises for student learning. In my reckoning, the most notable
exception to such a state of affairs is the pioneering book Numerical Heat Trans-
fer and Fluid Flow written by Professor Suhas V. Patankar. The book emphasises
control-volume discretisation (the main early step to obtaining numerical solutions)
based on physical principles and strives to help the reader to write his or her own
computer programs.
It is my pleasure and duty to acknowledge that writing of this book has been
influenced by the works of two individuals: Professor D. B. Spalding (FRS, formerly
at Imperial College of Science and Technology, London), who unified the fields of
heat, mass, and momentum transfer, and Professor S. V. Patankar (formerly at
University of Minnesota, USA), who, through his book, has made CFD so lucid
1
and SIMPLE. If the readers of this book find that I have mimicked writings of these
two pioneers from which several individuals (teachers, academic researchers, and
consultants) and organisations have benefited, I would welcome the compliment.
I have titled this book as Introduction to Computational Fluid Dynamics for two
reasons.Firstly,thebookisintendedtoserveasatextbookforastudentuninitiatedin
CFD but who has had exposure to the three courses mentioned in the first paragraph
of this preface at undergraduate and postgraduate levels. In this respect, the book
will also be found useful by teachers and practicing engineers who are increasingly
attracted to take refresher courses in CFD. Secondly, CFD, since its inception,
has remained an ever expanding field, expanding in its fundamental scope as well
as in ever new application areas. Thus, turbulent flows, which are treated in this
book through modelling, are already being investigated through direct numerical
simulation (DNS). Similarly, more appropriate constitutive relations for multiphase

1 The reader will appreciate the significance of capital letters in the text.