Modeling performance of a two-dimensional capsule in a microchannel flow: long-term lateral migration

Area of Science:

• Fluid dynamics
• Biophysics
• Microfluidics

Background:

• Understanding capsule behavior in microchannels is crucial for applications in drug delivery and diagnostics.
• Elastic capsules exhibit complex migration patterns influenced by flow dynamics and material properties.

Purpose of the Study:

• To numerically investigate the long-term lateral migration of a two-dimensional elastic capsule in a microchannel.
• To analyze the effects of initial position, membrane elasticity, and fluid viscosity on capsule migration dynamics.

Main Methods:

• A finite volume technique was employed to solve the fluid flow problem.
• A front tracking technique was used to capture and track the capsule membrane.
• The capsule was modeled as a liquid sphere with a linearly elastic membrane.

Main Results:

• Capsule migration speed is dependent on initial position, membrane dilation modulus, and viscosity ratio.
• Near-wall initial positions generally lead to faster lateral migration compared to near-center positions.
• The study observed discrepancies between simulated results and existing migration laws, particularly for near-center capsules.

Conclusions:

• Initial capsule position significantly impacts lateral migration, especially near the microchannel centerline.
• Lower membrane dilation modulus and viscosity ratio promote faster lateral migration.
• Further research is needed to fully understand the distinct behavior of capsules near the microchannel centerline.