Capillary filling dynamics of viscoelastic fluids
Aditya Bandopadhyay1, Uddipta Ghosh2, Suman Chakraborty3
1Advanced Technology Development Center, Indian Institute of Technology Kharagpur, Kharagpur-721302, India.
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|October 30, 2014
Summary
This study explores capillary filling with viscoelastic fluids, revealing unique behaviors in closed channels and a distinct viscoelastic regime during horizontal filling, contrasting with Newtonian fluid dynamics.
Area of Science:
- Fluid Mechanics
- Rheology
- Microfluidics
Background:
- Capillary filling dynamics are crucial in microfluidic applications.
- Viscoelastic fluids exhibit complex flow behaviors not fully captured by Newtonian models.
- The Phan-Thien-Tanner (PTT) model describes a class of viscoelastic fluids relevant to biofluids.
Purpose of the Study:
- To investigate capillary filling using the Phan-Thien-Tanner (PTT) viscoelastic fluid model.
- To differentiate the roles of gravity and rheology in capillary penetration oscillations.
- To analyze capillary filling in closed channels and compare it with open channels and Newtonian fluids.
Main Methods:
- Theoretical analysis of capillary filling dynamics.
- Consideration of both vertical and horizontal capillary filling scenarios.
- Scaling analysis to identify distinct flow regimes.
Main Results:
- Identified the influence of gravity and rheology on long-time oscillations in capillary penetration depth.
- Demonstrated fundamental differences in capillary filling for PTT versus Newtonian fluids in closed channels.
- Highlighted a unique viscoelastic regime in horizontal capillary filling, deviating from Washburn scaling.
Conclusions:
- The study provides insights into the distinct capillary filling behavior of viscoelastic fluids, particularly PTT fluids.
- Findings are relevant for microfluidic applications involving biofluids and complex fluids.
- The identified viscoelastic regime offers a new perspective on capillary flow in microchannels.
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