The mechanisms of jetting, vortex sheet, and vortex ring development in asymmetric bubble dynamics
The mechanisms of jetting, vortex sheet, and vortex ring development in asymmetric bubble dynamics
Bubble dynamics near a rigid boundary at Reynolds numbers of O(10–100) exhibit significant viscous effect, associated with ultrasonic cavitation and cavitation damage. We study this phenomenon experimentally using high-speed photography of spark-generated bubble oscillation in silicone oils, whose viscosity is about three orders larger than water. Comparing to bubbles in water, bubble surfaces in silicone oil are more stable and thus more cycles of oscillations may be observed and studied. Additionally, we investigate this phenomenon numerically using the volume of fluid method. We propose a non-reflective boundary condition, reducing the computational domain's dimensions tenfold based on the far-field asymptotic behavior. This paper pays particular attention in the mechanism for the bubble jetting, the vortex sheet, and the vortex ring development. Initially, a stagnation point at the bubble center moves away from the wall owing to asymmetric bubble expansion, leaving the bubble around the moment the bubble reaches its maximum volume. During this process, a vortex sheet forms inside the bubble. As the vortex sheet approaches the bubble interface, it transfers momentum to the gas–liquid interface, influencing the flow near the bubble wall. The high-pressure zone at the stagnation point drives the distal bubble surface to collapse first and fastest subsequently. This asymmetric collapse generates circulation around the bubble's side cross section, leading to the development of a vortex ring within the bubble gas at the outer rim of the decaying vortex sheet. The vortex ring, with its core inside the bubble gas, functions like a bearing system in accelerating the jet.
Yu, You
558b6c69-658b-4db5-a4d0-554995d8f888
Cui, Jie
052da08c-0505-484e-9574-7b2158692f3e
Smith, Warren R.
85801122-4774-4ae5-96b0-027731957ea8
Wang, Qianxi
9eb5fc2d-dea9-4003-ae17-0298eed5784d
Leighton, Timothy G.
3e5262ce-1d7d-42eb-b013-fcc5c286bbae
Yu, You
558b6c69-658b-4db5-a4d0-554995d8f888
Cui, Jie
052da08c-0505-484e-9574-7b2158692f3e
Smith, Warren R.
85801122-4774-4ae5-96b0-027731957ea8
Wang, Qianxi
9eb5fc2d-dea9-4003-ae17-0298eed5784d
Leighton, Timothy G.
3e5262ce-1d7d-42eb-b013-fcc5c286bbae
Yu, You, Cui, Jie, Smith, Warren R., Wang, Qianxi and Leighton, Timothy G.
(2023)
The mechanisms of jetting, vortex sheet, and vortex ring development in asymmetric bubble dynamics.
Physics of Fluids A, 35 (12), [123320].
(doi:10.1063/5.0177283).
Abstract
Bubble dynamics near a rigid boundary at Reynolds numbers of O(10–100) exhibit significant viscous effect, associated with ultrasonic cavitation and cavitation damage. We study this phenomenon experimentally using high-speed photography of spark-generated bubble oscillation in silicone oils, whose viscosity is about three orders larger than water. Comparing to bubbles in water, bubble surfaces in silicone oil are more stable and thus more cycles of oscillations may be observed and studied. Additionally, we investigate this phenomenon numerically using the volume of fluid method. We propose a non-reflective boundary condition, reducing the computational domain's dimensions tenfold based on the far-field asymptotic behavior. This paper pays particular attention in the mechanism for the bubble jetting, the vortex sheet, and the vortex ring development. Initially, a stagnation point at the bubble center moves away from the wall owing to asymmetric bubble expansion, leaving the bubble around the moment the bubble reaches its maximum volume. During this process, a vortex sheet forms inside the bubble. As the vortex sheet approaches the bubble interface, it transfers momentum to the gas–liquid interface, influencing the flow near the bubble wall. The high-pressure zone at the stagnation point drives the distal bubble surface to collapse first and fastest subsequently. This asymmetric collapse generates circulation around the bubble's side cross section, leading to the development of a vortex ring within the bubble gas at the outer rim of the decaying vortex sheet. The vortex ring, with its core inside the bubble gas, functions like a bearing system in accelerating the jet.
Text
123320_1_5.0177283
- Version of Record
More information
Submitted date: 20 September 2023
Accepted/In Press date: 14 November 2023
e-pub ahead of print date: 11 December 2023
Additional Information:
Funding Information:
The computations described in this paper were performed using the University of Birmingham's BlueBEAR HPC service, which provides a high-performance computing service to the University's research community. See http://www.birmingham.ac.uk/bear for more details. Valuable discussions were carried out with Dr. Cary Turangan, Institute of High Performance Computing, Singapore.
Publisher Copyright:
© 2023 Author(s).
Identifiers
Local EPrints ID: 485776
URI: http://eprints.soton.ac.uk/id/eprint/485776
PURE UUID: 2d0c8b84-6dc3-4a75-a76a-3d919096d9a6
Catalogue record
Date deposited: 18 Dec 2023 20:41
Last modified: 18 Mar 2024 02:39
Export record
Altmetrics
Contributors
Author:
You Yu
Author:
Jie Cui
Author:
Warren R. Smith
Author:
Qianxi Wang
Download statistics
Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.
View more statistics
