Page 49 - 48Fundamentals of Compressible Fluid Mechanics

1.3. HISTORICAL BACKGROUND 11

1.3.3.2 Nozzle flow
Romer et al 37 analyzed the isothermal flow in a nozzle. It is remarkable that chok-
as opposed to one (1). In general when the model assumed
.
The concept that
ing was found as
to be isothermal the choking occurs at
the choking point can move
from the throat was was in-
troduced by 38 the unknown
name.
It is very inter-
esting that the isothermal
nozzle was proposed by
Romer at el 1955 (who
was behind the adviser or
the student?). These re-
searchers where the first
one to realized that chok-
ing can occurs in different
aside
to the isothermal pipe. to insert the isothermal noz-
zle with external forces like
Mach number (
gravity and to show that chok-
ing location can move de-
1.3.3.3 Rayleigh Flow Fig. 1.4: Flow rate as a function of the back pressure taken pending on the direction of
from Stodola 1927 Steam and Gas Turbines the force.
39
Rayleigh was probably ,
the first to suggest a model
for frictionless flow with a constant heat transfer. Rayleigh’s work was during the
time when it was debatable as to whether there are two forms of energies (me-
chanical, thermal), even though Watt and others found and proved that they are
the same. Therefore, Rayleigh looked at flow without mechanical energy transfer
(friction) but only thermal energy transfer. In Rayleigh flow, the material reaches To find where Rayleigh did
understand that his model
choking point due to heat transfer, hence term “thermally choked” is used; no ad- leads to point flow
and graphical representation
ditional flow can occur. of the flow. The ques-

tion.
to insert information about the
detonation wave and relation-
1.3.3.4 Fanno Flow ship to Rayleigh line.
The most important model in compressible flow was suggested by Gino Fanno in
his Master’s thesis (1904). The model bears his name. Yet, according to Dr. Rudolf
37 Romer, I Carl Jr., and Ali Bulent Cambel, “Analysis of Isothermal Variable Area Flow,” Aircraft Eng.
vol. 27 no 322, p. 398 December 1955.
38 This undersign didn’t find the actual trace to the source of proposing this effect. However, some
astronomy books showing this effect in a dimensional form without mentioning the original researcher.
In dimensionless form, this phenomenon produces a dimensionless number similar to Ozer number
and therefor the name Ozer number adapted in this book.
39 As most of the history research has shown, there is also a possibility that someone found it earlier.
For example, Piosson was the first one to realize the shock wave possibility.