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Historical Background

In writing this book it became clear that there is more unknown and unwritten about the history of compressible fluid than known. While there are excellent books about the history of fluid mechanics (hydraulic) see for example book by Rouse^1.6. There are numerous sources dealing with the history of flight and airplanes (aeronautic)^1.7. Aeronautics is an overlapping part of compressible flow, however these two fields are different. For example, the Fanno flow and isothermal flow, which are the core of gas dynamics, are not part of aerodynamics. Possible reasons for the lack of written documentation are one, a large part of this knowledge is relatively new, and two, for many early contributors this topic was a side issue. In fact, only one contributor of the three main models of internal compressible flow (Isothermal, Fanno, Rayleigh) was described by any text book. This was Lord Rayleigh, for whom the Rayleigh flow was named. The other two models were, to the undersigned, unknown. Furthermore, this author did not find any reference to isothermal flow model earlier to Shapiro's book. There is no book^1.8that describes the history of these models. For instance, the question, who was Fanno, and when did he live, could not be answered by any of the undersigned's colleagues in University of Minnesota or elsewhere.

At this stage there are more questions about the history of compressible flow needing to be answered. Sometimes, these questions will appear in a section with a title but without text or with only a little text. Sometimes, they will appear in a footnote like this^1.9 For example, it is obvious that Shapiro published the erroneous conclusion that all the chocking occurred at M=1 in his article which contradicts his isothermal model. Additional example, who was the first to ``conclude'' the ``all'' the chocking occurs at M=1 ? Is it Shapiro?

Originally, there was no idea that there are special effects and phenomena of compressible flow. Some researchers even have suggested that compressibility can be ``swallowed'' into the ideal flow (Euler's equation's flow is sometimes referred to as ideal flow). Even before Prandtl's idea of boundary layer appeared, the significant and importance of compressibility emerged.

In the first half of nineteen century there was little realization that the compressibility is important because there were very little applications (if any) that required the understanding of this phenomenon. As there were no motivations to investigate the shock wave or choked flow both were treated as the same, taking compressible flow as if it were incompressible flow.

It must be noted that researchers were interested in the speed of sound even long before applications and knowledge could demand any utilization. The research and interest in the speed of sound was a purely academic interest. The early application in which compressibility has a major effect was with fire arms. The technological improvements in fire arms led to a gun capable of shooting bullets at speeds approaching to the speed of sound. Thus, researchers were aware that the speed of sound is some kind of limit.

In the second half of the nineteen century, Mach and Fliegner ``stumbled'' over the shock wave and choking, respectively. Mach observed shock and Fliegner measured the choking but theoretical science did not provide explanation for it (or was award that there is an explanation for it.).

In the twentieth century the flight industry became the pushing force. Understandably, aerospace engineering played a significant role in the development of this knowledge. Giants like Prandtl and his students like Van Karman , as well as others like Shapiro , dominated the field. During that time, the modern basic classes became ``solidified.'' Contributions by researchers and educators from other fields were not as dominant and significant, so almost all text books in this field are written from an aerodynamic prospective.

Subsections

Next: Early Developments Up: Introduction Previous: Why Compressible Flow is Index

Created by:Genick Bar-Meir, Ph.D.
On: 2007-11-21

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