## Abstract

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 language | English |
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Article number | A21 |

Number of pages | 29 |

Journal | Journal of Fluid Mechanics |

Volume | 933 |

Early online date | 23 Dec 2021 |

DOIs | |

Publication status | Published - 25 Feb 2022 |

## Keywords

- bubble dynamics
- multiphase flow
- plastic materials