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

Tools

Pourzahedi, Ali and Chaparian, Emad and Roustaei, Ali and Frigaard, Ian A. (2022) Flow onset for a single bubble in a yield-stress fluid. Journal of Fluid Mechanics, 933. A21. ISSN 0022-1120 (https://doi.org/10.1017/jfm.2021.1055)

[thumbnail of Pourzahedi-etal-JFM-2021-Flow-onset-for-a-single-bubble-in-a-yield-stress-fluid]
Preview
 Text. Filename: Pourzahedi_etal_JFM_2021_Flow_onset_for_a_single_bubble_in_a_yield_stress_fluid.pdf
Accepted Author Manuscript
License: Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 logo
Download (6MB)| Preview

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.

ORCID iDs

Pourzahedi, Ali, Chaparian, Emad ORCID logoORCID: https://orcid.org/0000-0002-5397-2079, Roustaei, Ali and Frigaard, Ian A.;
CORE (COnnecting REpositories)