Tensorial mobilities for accurate solution of transport problems in models with diffuse interfaces

Area of Science:

• Multiphysics simulations
• Continuum mechanics
• Materials science

Background:

• Phase-field models are crucial for simulating systems with distinct phases and diffuse interfaces.
• Transport phenomena in two-phase systems are often simplified using sharp-interface approximations.
• Understanding interface dynamics is key to accurate material behavior prediction.

Purpose of the Study:

• To analyze two-phase transport within phase-field models considering diffuse interfaces.
• To identify and characterize interface-specific phenomena arising from finite interface thickness.
• To propose a method for eliminating spurious interface effects in simulations.

Main Methods:

• Theoretical analysis of flux-potential gradient relationships in diffuse interfaces.
• Comparison of diffuse-interface models with sharp-interface approximations.
• Mathematical formulation of mobility as a tensor quantity.

Main Results:

• Finite interface thickness introduces a surface excess current and a potential jump.
• These effects are absent in sharp-interface models.
• Eliminating both effects simultaneously requires a tensorial mobility within interfaces.

Conclusions:

• The tensor nature of mobility in diffuse interfaces is essential for accurate two-phase transport modeling.
• This approach resolves surface excess current and potential jump artifacts.
• Enables more precise and efficient simulations of transport phenomena in materials with diffuse interfaces.