A multiblob approach to colloidal hydrodynamics with inherent lubrication

Area of Science:

• Computational physics
• Fluid dynamics
• Colloid science

Background:

• Accurate modeling of colloidal particle hydrodynamics is crucial for understanding complex fluid behavior.
• Existing methods often face computational limitations, especially for dense systems.

Purpose of the Study:

• To develop an intermediate resolution hydrodynamic model for colloidal particles.
• To accurately capture short-distance hydrodynamic responses and inter-particle interactions.
• To achieve computational efficiency for simulating dense colloidal systems.

Main Methods:

• A mixed Eulerian-Lagrangian formulation using overlapping Immersed Boundary kernels (blobs).
• A multiblob particle construction with 12 blobs on an icosahedron and one central blob.
• Utilizing Graphics Processing Units (GPUs) and Fast Fourier Transform (FFT) for the Poisson solver.

Main Results:

• The model accurately reproduces hydrodynamic responses and effective radii of spherical colloids.
• It naturally captures the soft lubrication regime and the viscosity increase in moderately dense systems (volume fraction up to 0.50).
• The model achieves significant computational speed-up for small particles relative to grid size.

Conclusions:

• The developed multiblob model provides an efficient and accurate method for simulating colloidal hydrodynamics.
• This approach enables the study of complex many-body hydrodynamic interactions in dense colloidal suspensions.
• The computational efficiency makes it suitable for large-scale simulations and further research.