Modeling ternary fluids in contact with elastic membranes.

Area of Science:

• Multiphase flow dynamics
• Computational fluid dynamics
• Soft matter physics

Background:

• Modeling complex fluid-structure interactions is crucial in various scientific fields.
• Existing models often face challenges in thermodynamic consistency and versatility.
• Ternary fluid systems interacting with elastic boundaries present unique modeling challenges.

Purpose of the Study:

• To introduce a thermodynamically consistent model for ternary fluid dynamics coupled with elastic membranes.
• To develop a versatile numerical framework for simulating these fluid-structure interactions.
• To validate the model's accuracy and demonstrate its applicability to complex geometries.

Main Methods:

• Free-energy modeling approach for fluid phases.
• Governing equations derived for ternary fluid flow and membrane dynamics.
• Numerical simulation using lattice Boltzmann method (Eulerian) and finite difference (Lagrangian) with immersed boundary coupling.
• Validation against Surface Evolver for capsule relaxation dynamics.

Main Results:

• A robust and thermodynamically consistent model for ternary fluid-membrane interactions was established.
• The numerical framework successfully simulated fluid-structure dynamics, including capsule deformation and capillary bridge formation.
• Galilean invariance of the proposed model was mathematically proven.
• The model demonstrated versatility in handling diverse geometries and fluid-structure configurations.

Conclusions:

• The presented model offers a powerful tool for simulating complex multiphase flow problems involving elastic boundaries.
• The validated numerical framework provides accurate predictions for fluid-structure interactions.
• This approach enhances the understanding of phenomena in soft matter physics and microfluidics.