Flow onset for a single bubble in a yield-stress fluid

Ali Pourzahedi, Emad Chaparian, Ali Roustaei, Ian A. Frigaard

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)
11 Downloads (Pure)


We use computational methods to determine the minimal yield stress required in order to hold static a buoyant bubble in a yield-stress liquid. The static limit is governed by the bubble shape, the dimensionless surface tension and the ratio of the yield stress to the buoyancy stress . For a given geometry, bubbles are static for Y_c]]>, which we determine for a range of shapes. Given that surface tension is negligible, long prolate bubbles require larger yield stress to hold static compared with oblate bubbles. Non-zero increases and for large the yield-capillary number determines the static boundary. In this limit, although bubble shape is important, bubble orientation is not. Two-dimensional planar and axisymmetric bubbles are studied.

Original languageEnglish
Article numberA21
Number of pages29
JournalJournal of Fluid Mechanics
Early online date23 Dec 2021
Publication statusPublished - 25 Feb 2022


  • bubble dynamics
  • multiphase flow
  • plastic materials


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