Low Reynolds Number Interactions between Colloidal Particles near the Entrance to a Cylindrical Pore

Area of Science:

• Colloidal science
• Fluid dynamics
• Computational physics

Background:

• Understanding colloidal particle behavior at pore entrances is crucial for various applications, including filtration and drug delivery.
• Existing analytical and semi-analytical methods struggle to accurately capture complex interparticle and particle-pore hydrodynamic interactions.

Purpose of the Study:

• To numerically investigate the interaction between stable colloidal particles and a pore entrance.
• To analyze the influence of particle size relative to pore size on interaction dynamics.
• To explore the interplay of hydrodynamic and colloidal forces governing particle flow.

Main Methods:

• Adapted a front-tracking technique based on finite difference solutions of Navier-Stokes equations.
• Employed a two-dimensional simulation with both deformable and nondeformable particles.
• Explicitly represented particle-liquid interfaces using a moving unstructured grid on a stationary Cartesian grid.

Main Results:

• The numerical method naturally accounts for complex interparticle and particle-pore hydrodynamic interactions.
• Simulations analyzed the motion of two- and three-particle systems towards a pore.
• The competition between hydrodynamic and colloidal forces dictates particle flow behavior near the pore entrance.

Conclusions:

• The developed numerical method effectively simulates colloidal particle interactions at pore entrances.
• Particle flow behavior is dependent on flow velocity and the pore-to-particle size ratio.
• Simulation results align qualitatively with experimental observations, validating the numerical approach.