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Fingering stabilization and adhesion force in the lifting flow with a fluid annulus
Írio M Coutinho1, Pedro H A Anjos2, Rafael M Oliveira2
1Departamento de Física, Universidade Federal de Pernambuco, CCEN, Recife, Pernambuco 50670-901, Brazil.
Physical Review. E
|February 17, 2024
Summary
Introducing a fluid annulus layer stabilizes viscous fingering instabilities in lifting Hele-Shaw flows. This method controls interfacial disturbances without significantly altering adhesion forces, offering a new control strategy.
Area of Science:
- Fluid dynamics
- Interfacial phenomena
- Instability control
Background:
- Lifting Hele-Shaw cell flow involves stretching viscous droplets between plates.
- Viscous fingering instabilities, a type of Saffman-Taylor instability, occur at the air-oil interface and are difficult to control.
- Controlling interfacial disturbances is crucial for technological and industrial applications.
Purpose of the Study:
- To propose and analyze an alternative method for controlling interfacial disturbances in lifting Hele-Shaw flows.
- To investigate the stabilizing effect of an intermediate fluid annulus on a central oil droplet.
- To determine the influence of the fluid annulus on adhesion forces.
Main Methods:
- A modified Hele-Shaw cell configuration with a three-fluid, two-interface, doubly connected system was analyzed.
- A second-order, perturbative mode-coupling approach was used to study morphological and stability behaviors.
- Adhesion forces were calculated for both stable and unstable interface conditions.
Main Results:
- The intermediate fluid ring significantly stabilizes the central oil droplet's interface.
- Stabilization effectiveness depends on the ring's viscosity and thickness.
- Adhesion forces remain largely unchanged with a thin fluid envelope, regardless of interface stability.
Conclusions:
- An intermediate fluid annulus is an effective strategy to stabilize viscous fingering in lifting Hele-Shaw flows.
- The fluid annulus offers a controllable method for managing interfacial disturbances.
- The presence of fingering at the ring's boundaries has a negligible impact on the adhesion force.
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