Shear viscosity of inhomogeneous fluids

Area of Science:

• Computational physics and chemistry
• Fluid dynamics
• Statistical mechanics

Background:

• Understanding shear viscosity in inhomogeneous fluids is crucial for various applications.
• Existing models, like the local average density model, face challenges in accurately predicting viscosity profiles in low-density inhomogeneous systems.

Purpose of the Study:

• To investigate the impact of density inhomogeneities on local shear viscosity.
• To evaluate the performance of the local average density model for inhomogeneous fluids.
• To develop an improved approach for calculating shear viscosity in low-density inhomogeneous fluids.

Main Methods:

• Molecular dynamics simulations were employed to model inhomogeneous fluids.
• The study analyzed the effects of density inhomogeneities with varying wavelengths.
• Local shear viscosity was computed and compared with theoretical models.

Main Results:

• The local average density model with a weight function accurately describes viscosity profiles for dense inhomogeneous fluids.
• This model fails to predict viscosity profiles correctly for low-density inhomogeneous fluids.
• An improved approach incorporating density gradients in the local translational contribution enhances accuracy for low-density systems.

Conclusions:

• Density inhomogeneities significantly affect local shear viscosity.
• A density gradient approach is necessary for accurate viscosity calculations in low-density inhomogeneous fluids.
• The findings provide a more robust method for simulating and understanding fluid behavior in complex environments.