Internal flow

In fluid mechanics, internal flow is a flow wherein the fluid is completely confined by inner surfaces of an item (e.g. a tube).¹ Hence the boundary layer is unable to develop without eventually being constrained. The internal flow configuration represents a convenient geometry for heating and cooling fluids used in chemical processing, environmental control, and energy conversion technologies. Internal flow is fully dominated by viscosity throughout the flow field.²

An example includes flow in a pipe.

References

Çengel, Yunus A. (2014). Heat and Mass Transfer : Fundamentals and Applications (5th ed.). NY: McGraw-Hill Higher Education. p. 449. ISBN 9780077654764.
Çengel, Yunus A.; Cimbala, John M. (2006). Fluid mechanics: fundamentals and applications. McGraw-Hill series in mechanical engineering. Boston, Mass.: McGraw-Hill Higher Education. p. 10. ISBN 978-0-07-247236-3.

E. M. Greitzer; C. S. Tan; M. B. Graf (26 February 2007). Internal Flow: Concepts and Applications. Cambridge University Press. ISBN 978-1-139-45111-6.

[1] Çengel, Yunus A. (2014). Heat and Mass Transfer : Fundamentals and Applications (5th ed.). NY: McGraw-Hill Higher Education. p. 449. ISBN 9780077654764.

[2] Çengel, Yunus A.; Cimbala, John M. (2006). Fluid mechanics: fundamentals and applications. McGraw-Hill series in mechanical engineering. Boston, Mass.: McGraw-Hill Higher Education. p. 10. ISBN 978-0-07-247236-3.

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