Different bending models predict different dynamics of sedimenting elastic trumbbells

Area of Science:

• Fluid dynamics
• Polymer physics
• Computational physics

Background:

• Elastic filaments in viscous fluids are modeled using bead-spring approximations.
• Hydrodynamic interactions are crucial for understanding filament dynamics.

Purpose of the Study:

• To investigate the impact of different bending models on elastic filament dynamics.
• To compare the harmonic and Kratky-Porod bending models for trumbbell filaments.

Main Methods:

• Theoretical and numerical examination of elastic trumbbells.
• Utilizing the bead-spring approximation and Rotne-Prager mobility matrix.
• Analysis of harmonic and Kratky-Porod bending potentials.

Main Results:

• The harmonic bending model yields stable stationary configurations and periodic oscillations for trumbbells.
• The Kratky-Porod model can produce spurious dynamics with large, unrealistic bending angles.

Conclusions:

• The Kratky-Porod model has limited applicability for bead-spring elastic filaments, especially at larger bending angles.
• Accurate modeling of elastic filament dynamics requires careful selection of bending potentials.