Transition between "clusters" and "stratified" flow regimes in the pneumatic conveying system - Gas flow driven granular jump

Artur J. Jaworski, Tomasz Dyakowski, Michael Doby

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


This paper discusses the occurrence and the mechanisms behind a previously unreported phenomenon of the "granular jump" observed in the gas-solids flow within the pneumatic conveying system. From the phenomenological point of view the phenomenon resembles the already known processes such as hydraulic jumps in shallow water or propagation of bores in gravity driven avalanches, although clearly the flow itself is driven by the aerodynamic forces related to the gas flow and the behaviour of the front of the "jump" itself, as discussed in the paper, is modified significantly by their presence. A series of high-speed camera visualisations are presented, which focus on this unusual behaviour of the flow on the border-line between cluster and stratified flow regimes in a horizontal pipe. Some similarities are drawn between the observed phenomenon and the broader class of problems exhibiting transition between super- and sub-critical flows. The fluid dynamical phenomena are discussed and the results obtained are compared quantitatively with simple theoretical models.

Original languageEnglish
Title of host publicationAIChE Annual Meeting, Conference Proceedings 2006
Number of pages9
Publication statusPublished - 2006
Externally publishedYes
EventAmerican Institute of Chemical Engineers Spring Meeting & 5th World Congress on Particle Technology - Orlando, United States
Duration: 23 Apr 200627 Apr 2006 (Link to Conference Website)


ConferenceAmerican Institute of Chemical Engineers Spring Meeting & 5th World Congress on Particle Technology
CountryUnited States
Internet address


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