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Stress correlations and stress memory kernels in viscoelastic fluids.
Niklas Grimm1, Jörg Baschnagel2, Alexander N Semenov2
1University of Konstanz, D-78457 Konstanz, Germany. Matthias.Fuchs@uni-konstanz.de.
Soft Matter
|May 9, 2025
Summary
We explored stress fluctuations in viscoelastic fluids, linking stress correlations to transport kernels. Our findings predict shear stress behavior in 2D and 3D systems, aligning with simulations.
Area of Science:
- Rheology
- Condensed Matter Physics
- Statistical Mechanics
Background:
- Viscoelastic fluids exhibit complex stress dynamics.
- Understanding spatio-temporal stress correlations is crucial for material science.
Purpose of the Study:
- To establish a theoretical framework for stress fluctuations in viscoelastic materials.
- To predict the behavior of stress correlations in different dimensions.
Main Methods:
- Relating stress auto-correlation functions to generalized Onsager transport kernels.
- Utilizing Zwanzig-Mori decomposition and a stress noise approach.
- Analyzing correlations in both finite and long wavelength limits.
Main Results:
- A general relation between stress correlations and transport kernels was derived.
- Power-law stress correlations in fluid states were re-derived.
- Predictions for shear stress correlation function distance dependence in 2D and 3D systems were made.
Conclusions:
- The theoretical framework accurately describes stress fluctuations in viscoelastic fluids.
- The derived predictions show good agreement with simulation data for hard-sphere mixtures.
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