Page 41 - 48Fundamentals of Compressible Fluid Mechanics

1.3. HISTORICAL BACKGROUND 3
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tic) . 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 under-
signed, unknown. Furthermore, this author did not find any reference to isothermal
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flow model earlier to Shapiro’s book. There is no book that 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
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a footnote like this . For example, it obvious that Shapiro published the erroneous
conclusion that all the chocking occurred at
in his article which contradicts
his isothermal model. Additional example, who was the first to “conclude” the “all”
? Is it Shapiro?
Orientally, there was no idea there are special effects and phenomena
of compressible flow. Some researchers even have suggested that compressibility
the chocking occurs at
can be “swallowed” into the ideal flow (Euler’s equation’s flow is sometimes re-
ferred 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 Flinger “stumbled”
over the shock wave and choking, respectively. Mach observed shock and Flinger
7 Anderson, J. D., Jr. 1997. A History of Aerodynamics: And Its Impact on Flying Machines, Cam-
bridge University Press, Cambridge, England.
8 The only remark found about Fanno flow that it was taken from the Fanno Master thesis by his
adviser. Here is a challenge: find any book describing the history of the Fanno model.
9 Who developed the isothermal model? The research so far leads to Shapiro. Perhaps this flow
should be named after the Shapiro. Is there any earlier reference to this model?