# Fundamentals of Compressible Flow Mechanics

Genick Bar-Meir

Copyright Year: 2004

Last Update: 2021

Publisher: Potto Project

Language: English

## Formats Available

## Conditions of Use

Free Documentation License (GNU)

Free Documentation License (GNU)

## Reviews

This book is supposed to talk about the fundamentals or introduction level of compressible flow, but the authors don't provide definitions on lots of concepts. read more

This book is supposed to talk about the fundamentals or introduction level of compressible flow, but the authors don't provide definitions on lots of concepts.

Typos are found across the text. Some paragraph is not smooth logically.

The author gives references when arguments are mentioned. And new material should be easy to appended into it.

Some paragraphs are not logically clear. And some grammar mistakes can be found across the book.

The author definitely has his understanding on compressible flow and the sketch of this book is fine.

Modularity is fine. However, some basic concepts are not well explained.

The structure is good. Covering the basics of thermal dynamics and fluid mechanics, then followed by the compressible topics.

I would suggest using a profession typeset software like latex to re-format this book. The margins on odd and even pages are not same and this brings additional labor for readers.

Unfortunately, some grammatical errors are found, across the whole book. And there are typos as well.

I didn't see any sign of this.

I would suggestion to re-format this book using Latex.

The textbook covers the major topics one would expect in an introductory textbook. Major topics from an introductory compressible flow course like the speed of sound, Rayleigh and Fanno flow, variable area flows, normal and oblique shocks, and... read more

The textbook covers the major topics one would expect in an introductory textbook. Major topics from an introductory compressible flow course like the speed of sound, Rayleigh and Fanno flow, variable area flows, normal and oblique shocks, and Prandtl-Meyer expansions have their own chapters. The book also includes a review of thermodynamics and basic fluid mechanics.

There are several chapters that do not appear in standard compressible flow textbooks. These chapters deal with evacuating chambers and isothermal flow but these chapters are not as polished as the more standard chapters. As a work in progress, there are some sections of the textbook which are unfinished or have notes to the reader to ignore incomplete sections.

The textbook only mentions computational fluid dynamics briefly in the introduction and does not have any in-depth material on CFD issues related to compressible flow.

The book has some compressible flow tables included within the body of the text, but no dedicated appendices like most compressible flow textbooks. The webpage for the textbook does have links to HTML, PDF, and the latex source files for compressible flow tables but they are on a supplemental download page and may not be immediately obvious to the reader. The download page also features a compressible flow equation reference and a computer program for gas dynamics calculations.

The book includes a good table of contents, list of figures, and list of tables. There is a subject index, but the coverage could be improved. For example, there is a chapter on Isentropic flow but the word isentropic does not appear in the subject index. There is also an authors index for readers that are interested in the work of a specific researcher.

The content of the book is generally accurate. I found no significant errors during my read-through, though over the course of the revision process typos have been found and corrected. Unfortunately, the textbook has not been updated since 2013 and there are still unfinished chapters included in the manuscript. In the main compressible flow chapters (normal and oblique shocks, Prandtl-Meyer expansion, Rayleigh and Fanno Flow, variable area flow, isentropic flow), the chapters are more polished and accurate.

When dealing with the mathematics and science of compressible flow, the text is unbiased. In the introduction and in some of the supplemental materials the author takes a more argumentative tone that may be off-putting to some readers.

I see no issues with the relevance or longevity of most of the text. The only places with issues are the unfinished chapters that are not part of a traditional compressible flow course. The revision log was active from 2006-2013, but updates to the main textbook page and to the text seem to have stopped. The source files for the textbook do not appear to be available on the main download page any longer, so anyone looking to modify or update the text may find it a challenge to do so.

The mathematics of the text are presented clearly and often in more detail than is found in other compressible flow textbooks. The text itself is written in a generally accessible style, but there are often typographical or grammatical issues that may distract the reader from the meaning of the text. A nomenclature is included at the beginning of the text but could be expanded to give more comprehensive coverage.

The book is consistent with terminology both internally and with generally accepted nomenclature. Important equations are consistently boxed and highlighted to set them off from the rest of the text.

The only significant inconsistency is in the state of the incomplete chapters, as they are significantly shorter and presented in less detail than the main compressible flow chapters.

The book is very modular and could be easily reorganized. Long chapters are broken up into sections and subsections. Example problems are spread throughout the text to break up explanations.

The organization of the book is logical with each chapter representing a major topic in compressible flow. Unlike most compressible flow textbooks, the tables for isentropic, normal shock, one-dimensional heat addition, one-dimensional friction, and Prandtl-Meyer expansions are not included as an appendix. Example table appears within the text, with the reader often referred to the Potto-GDC, a gas dynamics calculator available for download on the site, which can calculate the properties for a given case. There are supplemental tables available for viewing or download on the textbook webpage.

The most recent PDF version of the book has fewer interface issues and would rate a higher score on its own. Unfortunately, when performing a web search for the book, most readers will find the online textbook which has several significant issues. First, the book is several revisions behind the PDF version of the text. This could cause difficulties with students viewing the online textbook vs. the PDF version. Second, at the time of this review, the PDF download of the textbook does not seem to be available on the Potto project page. This reduced availability for the latest revision of the text greatly decreases the usefulness of the book as the later revisions added much-needed example problems and polish to the main compressible flow chapters.

If the availability of the latest PDF were corrected and the webpage updated, this score would increase.

The text has many grammatical and typographical errors throughout the text. Some of these issues were caught and corrected when the textbook was revised more frequently; however, a significant number of issues still remain. In the main compressible flow chapters, these issues are relatively minor but could confuse a first-time reader as they have to work harder to parse the text.

I did not find any issues with the cultural relevance of the text.

This review is for the PDF version 0.4.9.8. The online version of the textbook is several revisions behind and does not have many important revisions and content additions that the PDF version does. Unfortunately, the textbook website has not been updated since 2013 and the more recent PDF version is not available on the textbook webpage at the time of this review. It is a promising start to an open compressible flow textbook, but I would have reservations adopting it as a sole or primary text for a course until the availability issues were addressed.

## Table of Contents

- 1 Introduction
- 2 Review of Thermodynamics
- 3 Basic of Fluid Mechanics
- 4 Speed of Sound
- 5 Isentropic Flow
- 6 Normal Shock
- 7 Normal Shock in Variable Duct Areas
- 8 Nozzle Flow With External Forces
- 9 Isothermal Flow
- 10 Fanno Flow
- 11 Rayleigh Flow
- 12 Evacuating SemiRigid Chambers
- 13 Evacuating under External Volume Control
- 14 Oblique Shock
- 15 Prandtl-Meyer Function
- A Computer Program
- B Oblique Shock History

## Ancillary Material

## About the Book

This book deals with an introduction to the flow of compressible substances (gases). The main difference between compressible flow and almost incompressible flow is not the fact that compressibility has to be considered. Rather, the difference is in two phenomena that do not exist in incompressible flow. The first phenomenon is the very sharp discontinuity (jump) in the flow in properties. The second phenomenon is the choking of the flow. Choking is when downstream variations don't effect the flow. Though choking occurs in certain pipe flows in astronomy, there also are situations of choking in general (external) flow.

## About the Contributors

### Author

**Genick Bar-Meir** holds a Ph.D. in Mechanical Engineering from University of Minnesota and a Master in Fluid Mechanics from Tel Aviv University. Dr. Bar-Meir was the last student of the late Dr. R.G.E. Eckert. Much of his time has been spend doing research in the field of heat and mass transfer (related to renewal energy issues) and this includes fluid mechanics related to manufacturing processes and design. Currently, he spends time writing books (there are already three very popular books) and softwares for the POTTO project (see Potto Prologue). The author enjoys to encourage his students to understand the material beyond the basic requirements of exams.

In his early part of his professional life, Bar-Meir was mainly interested in elegant models whether they have or not a practical applicability. Now, this author’s views had changed and the virtue of the practical part of any model becomes the essential part of his ideas, books and software.

He developed models for Mass Transfer in high concentration that became a building blocks for many other models. These models are based on analytical solution to a family of equations. As the change in the view occurred, Bar-Meir developed models that explained several manufacturing processes such the rapid evacuation of gas from containers, the critical piston velocity in a partially filled chamber (related to hydraulic jump), application of supply and demand to rapid change power system and etc. All the models have practical applicability. These models have been extended by several research groups (needless to say with large research grants). For example, the Spanish Comision Interministerial provides grants TAP97-0489 and PB98-0007, and the CICYT and the European Commission provides 1FD97-2333 grants for minor aspects of that models. Moreover, the author’s models were used in numerical works, in GM, British industry, Spain, and Canada.

In the area of compressible flow, it was commonly believed and taught that there is only weak and strong shock and it is continue by Prandtl–Meyer function. Bar–Meir discovered the analytical solution for oblique shock and showed that there is a quiet bu?er between the oblique shock and Prandtl–Meyer. He also build analytical solution to several moving shock cases. He described and categorized the filling and evacuating of chamber by compressible fluid in which he also found analytical solutions to cases where the working fluid was ideal gas. The common explanation to Prandtl–Meyer function shows that flow can turn in a sharp corner. Engineers have constructed design that based on this conclusion. Bar-Meir demonstrated that common Prandtl–Meyer explanation violates the conservation of mass and therefor the turn must be around a finite radius. The author’s explanations on missing diameter and other issues in fanno flow and “naughty professor’s question” are used in the industry.

In his book “Basics of Fluid Mechanics”, Bar-Meir demonstrated several things which include Pushka equation, dealing with the pressure accounted the slight compressibility (a ?nite Bulk Modulus effect), speed of sound in slightly compressible liquid. He showed the relationship between the wavy surface and the multi–phases flow.

The author lives with his wife and three children. A past project of his was building a four stories house, practically from scratch. While he writes his programs and does other computer chores, he often feels clueless about computers and programing. While he is known to look like he knows a lot a lot about many things, the author just know to learn quickly. The author spent years working on the sea (ships) as a engine sea officer but now the author prefers to remain on a solid ground.