Novel lattice Boltzmann method for simulation of strongly shear thinning viscoelastic fluids

• Published in: International journal for numerical methods in fluids 2025-02, Vol.97 (2), p.164-187
• Main Authors: Kellnberger, Richard, Jüngst, Tomasz, Gekle, Stephan
• Format: Article
• Language: English
• Subjects: Addition polymerization; Alginates; Alginic acid; biofluidics; Cellulose; Fluids; immersed boundary; laminar flow; lattice Boltzmann; Liquids; Mathematical models; Methylcellulose; microfluidics; non‐Newtonian; Polymers; Seaweed meal; Shear; Shear thinning (liquids); Stability; Thinning; Viscoelastic fluids; Viscoelastic liquids; Viscoelasticity; Viscosity; Viscosity ratio
• ISSN: 0271-2091; 1097-0363
• DOI: 10.1002/fld.5335

The simulation of viscoelastic liquids using the Lattice–Boltzmann method (LBM) in full three dimensions remains a formidable numerical challenge. In particular the simulation of strongly shear‐thinning fluids, where the ratio between the high‐shear and low‐shear viscosities is large, is often prevented by stability problems. Here we present a novel approach to overcome this issue. The central idea is to artificially increase the solvent viscosity which allows the method to benefit from the very good stability properties of the LBM. To compensate for this additional viscous stress, the polymer stress is reduced by the same amount. We apply this novel method to simulate two realistic cell carrier fluids, methyl cellulose and alginate solutions, of which the latter exhibits a viscosity ratio exceeding 10,000. We develop a novel viscosity shuffling Lattice–Boltzmann method to enable the simulation of shear thinning viscoelastic fluids with high viscosity ratios.