View source for Isothermal flow

{{Short description|Model of fluid flow}}
{{thermodynamics}}
{{expert needed|Physics|date=August 2012|reason=See Talk page, section "???"}}
{{More footnotes|date=April 2021}}

'''Isothermal flow''' is a model of [[Compressible flow|compressible fluid flow]] whereby the flow remains at the same [[temperature]] while flowing in a conduit.<ref>Shapiro, A.H., ''The Dynamics and Thermodynamics of Compressible Fluid Flow, Volume 1'', Ronald Press, 1953.</ref> In the model, [[heat]] transferred through the walls of the conduit is offset by [[friction]]al heating back into the flow. Although the flow temperature remains constant, a change in stagnation temperature occurs because of a change in velocity. The interesting part of this flow is that the flow is choked at <math>1/\sqrt{k}</math> and not at [[Mach number]] equal to one as in the case of many other model such as [[Fanno flow]].  This fact applies to real gases as well as ideal gases.

For the important practical case of a [[gas]] flow through a long tube, the model has applicability in situations where distance is relatively long and heat transfer is relatively rapid so temperature can be treated, for engineering purposes, as a constant. This model also has applicability as upper boundary to Fanno flow.

==See also==
*[[Fanno flow]]
*[[Isentropic process]]
*[[Rayleigh flow]]

==References==
{{Reflist}}

==External links==
*[http://www.potto.org/gasDynamics/gasDynamics.php  Fundamentals of compressible Flow]

[[Category:Fluid dynamics]]