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Microscopic theory for the pair correlation function of liquidlike colloidal suspensions under shear flow.
Luca Banetta1, Francesco Leone2, Carmine Anzivino2
1Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy.
Physical Review. E
|November 18, 2022
Summary
This study develops a theoretical framework for concentrated hard-sphere colloidal suspensions under shear flow. The model accurately predicts microscopic structure and suggests shear-induced phase transitions.
Area of Science:
- Colloidal science
- Soft matter physics
- Fluid dynamics
Background:
- Understanding the microscopic structure of concentrated colloidal suspensions is crucial for predicting their bulk properties.
- Shear flows significantly alter the behavior and structure of these suspensions, leading to complex phenomena.
Purpose of the Study:
- To develop a theoretical framework for investigating the microscopic structure of concentrated hard-sphere colloidal suspensions under strong shear flows.
- To incorporate the effects of convective diffusion and hydrodynamic interactions within the theoretical model.
Main Methods:
- Solving the pair Smoluchowski equation with shear using matched asymptotics in compressing and extensional sectors.
- Constructing a potential of mean force that includes flow field effects on pair correlations.
- Utilizing the Percus-Yevick relation as a closure for the Ornstein-Zernike integral equation.
Main Results:
- The theoretical framework shows good agreement with existing numerical results for various packing fractions and Péclet (Pe) numbers.
- Scaling laws for the pair correlation function at contact were extracted.
- A consistent enhancement of the structure factor S(k) at k→0 was predicted with increasing Pe number.
Conclusions:
- The developed theoretical framework provides accurate predictions for the microscopic structure of sheared colloidal suspensions.
- The predicted enhancement of the structure factor may indicate a shear-induced phase transition from an isotropic to a nonuniform phase.
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