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 |
|---|---|
| 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 |
Funding
This research has been carried out at the University of British Columbia (UBC). Financial support for the study was provided by IOSI/COSIA and NSERC (project numbers CRDPJ 537806-18 and IOSI Project 2018-10). This funding is gratefully acknowledged. The authors also express their gratitude to the University of British Columbia for financial support via the 4YF scholarship (A.P.). A.R. acknowledges the financial support by Iran's national science foundation (INSF) through contract 97013654. This computational research was also partly enabled by infrastructure provided by Compute Canada/Calcul Canada ( www.computecanada.ca ).
Keywords
- bubble dynamics
- multiphase flow
- plastic materials