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Next: How This Book Was Up: Prologue For This Book Previous: Version 0.4   Index

Version 0.3

In the traditional class of compressible flow it is assumed that the students will be aerospace engineers or dealing mostly with construction of airplanes and turbomachinery. This premise should not be assumed. This assumption drives students from other fields away from this knowledge. This knowledge should be spread to other fields because it needed there as well. This ``rejection'' is especially true when students feel that they have to go through a ``shock wave'' in their understanding.

This book is the second book in the series of POTTO project books. POTTO project books are open content textbooks. The reason the topic of Compressible Flow was chosen, while relatively simple topics like fundamentals of strength of material were delayed, is because of the realization that manufacture engineering simply lacks fundamental knowledge in this area and thus produces faulty designs and understanding of major processes. Unfortunately, the undersigned observed that many researchers who are dealing with manufacturing processes are lack of understanding about fluid mechanics in general but particularly in relationship to compressible flow. In fact one of the reasons that many manufacturing jobs are moving to other countries is because of the lack of understanding of fluid mechanics in general and compressible in particular. For example, the lack of competitive advantage moves many of the die casting operations to off shore9. It is clear that an understanding of Compressible Flow is very important for areas that traditionally have ignored the knowledge of this topic10.

As many instructors can recall from their time as undergraduates, there were classes during which most students had a period of confusion, and then later, when the dust settled, almost suddenly things became clear. This situation is typical also for Compressible Flow classes, especially for external compressible flow (e.g. flow around a wing, etc.). This book offers a more balanced emphasis which focuses more on internal compressible flow than the traditional classes. The internal flow topics seem to be common for the ``traditional'' students and students from other fields, e.g., manufacturing engineering.

This book is written in the spirit of my adviser and mentor E.R.G. Eckert. Who, aside from his research activity, wrote the book that brought a revolution in the heat transfer field of education. Up to Eckert's book, the study of heat transfer was without any dimensional analysis. He wrote his book because he realized that the dimensional analysis utilized by him and his adviser (for the post doc), Ernst Schmidt, and their colleagues, must be taught in engineering classes. His book met strong criticism in which some called to burn his book. Today, however, there is no known place in world that does not teach according to Eckert's doctrine. It is assumed that the same kind of individuals who criticized Eckert's work will criticize this work. This criticism will not change the future or the success of the ideas in this work. As a wise person says ``don't tell me that it is wrong, show me what is wrong''; this is the only reply. With all the above, it must be emphasized that this book will not revolutionize the field even though considerable new materials that have never been published are included. Instead, it will provide a new emphasis and new angle to Gas Dynamics.

Compressible flow is essentially different from incompressible flow in mainly two respects: discontinuity (shock wave) and choked flow. The other issues, while important, are not that crucial to the understanding of the unique phenomena of compressible flow. These unique issues of compressible flow are to be emphasized and shown. Their applicability to real world processes is to be demonstrated11.

The book is organized into several chapters which, as a traditional textbook, deals with a basic introduction of thermodynamics concepts (under construction). The second chapter deals with speed of sound. The third chapter provides the first example of choked flow (isentropic flow in a variable area). The fourth chapter deals with a simple case of discontinuity (a simple shock wave in a nozzle). The next chapter is dealing with isothermal flow with and without external forces (the moving of the choking point), again under construction. The next three chapters are dealing with three models of choked flow: Isothermal flow12, Fanno flow and Rayleigh flow. First, the Isothermal flow is introduced because of the relative ease of the analytical treatment. Isothermal flow provides useful tools for the pipe systems design. These chapters are presented almost independently. Every chapter can be ``ripped'' out and printed independently. The topics of filling and evacuating of gaseous chambers are presented, normally missed from traditional textbooks. There are two advanced topics which included here: oblique shock wave, and properties change effects (ideal gases and real gases) (under construction). In the oblique shock, for the first time analytical solution is presented, which is excellent tool to explain the strong, weak and unrealistic shocks. The chapter on one-dimensional unsteady state, is currently under construction.

The last chapter deals with the computer program, Gas Dynamics Calculator (CDC-POTTO). The program design and how to use the program are described (briefly).

Discussions on the flow around bodies (wing, etc), and Prandtl-Meyer expansion will be included only after the gamma version unless someone will provide discussion(s) (a skeleton) on these topics.

It is hoped that this book will serve the purposes that was envisioned for the book. It is further hoped that others will contribute to this book and find additional use for this book and enclosed software.

next up previous index
Next: How This Book Was Up: Prologue For This Book Previous: Version 0.4   Index
Created by:Genick Bar-Meir, Ph.D.
On: 2007-11-21