On the method of characteristics in highly compressible flows

Research output: Chapter in Book/Report/Conference proceedingConference contribution


The method of characteristics (MOC) is widely used in simulations of transient liquid flows. Nearly always, the method is simplified by key assumptions that the speed of sound is (i) constant and (ii) very much larger than the fluid velocity. This paper describes how MOC can be used in transient gas flows even when these assumptions cannot reasonably be made. Examples include flows at large (but subsonic) Mach number and strongly compressible flows in long pipes with skin friction and/or heat transfer. Four formulations of the basic equations are presented and their advantages and disadvantages are explained. The simplest of these, based on pressure p, density p and velocity U, closely resembles conventional water-hammer formulations. The most powerful formulation, based on temperature T, specific entropy s and Mach number M, has special advantages in the representation of a path-line equation that is always necessary in addition to the two wave­-path equations. This formulation can yield stable solutions for all subsonic flows (M < 1 ).
Original languageEnglish
Title of host publicationProceedings of the 14th International Conference on Pressure Surges
EditorsSarah E. L. Jones
Place of PublicationEindhoven
PublisherEindhoven University of Technology
Number of pages15
ISBN (Print)9789038657103
Publication statusPublished - 2023
Event14th International Conference on Pressure Surges - Eindhoven University of Technology, Eindhoven, Netherlands
Duration: 12 Apr 202314 Apr 2023


Conference14th International Conference on Pressure Surges
Internet address


  • one-dimensional
  • unsteady
  • compressible pipe-flow
  • momentum correction factor
  • energy correction factor


Dive into the research topics of 'On the method of characteristics in highly compressible flows'. Together they form a unique fingerprint.

Cite this