Computing bulk and shear viscosities from simulations of fluids with dissipative and stochastic interactions

Jung, Gerhard; Schmid, Friederike

doi:10.1063/1.4950760

Cited by 33 publications

(42 citation statements)

References 28 publications

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“…We choose the DPD parameters, γ = 5 τ σ −2 , density ρ = 3 σ −3 and the time step ∆t = 0.005τ . The shear viscosity is η = 1.28 τ σ −3 [47] and the solvent diffusion coefficient can be approximated to D s = 0.75σ 2 τ −1 [46].…”

Section: Computer Simulations and Modelingmentioning

confidence: 99%

Fluctuation–dissipation relations far from equilibrium: a case study

Jung

Schmid

2021

Soft Matter

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Section: Computer Simulations and Modelingmentioning

confidence: 99%

Fluctuation–dissipation relations far from equilibrium: a case study

Jung

Schmid

2021

Soft Matter

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“…This definition of the stress does not include the dissipative and random force contributions. It has been pointed out that these forces should, in fact, be included; [32][33][34] however, recently Hansen et al 35 noted that the viscosity evaluated from the Green-Kubo integral of the stress autocorrelation where definition (3) is used gives the correct hydrodynamic relaxation times.…”

Section: The Rose Model and Methodologymentioning

confidence: 99%

ROSE bitumen: Mesoscopic model of bitumen and bituminous mixtures

Lemarchand

Greenfield

Dyre

et al. 2018

The Journal of Chemical Physics

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We present a mesoscopic model for bitumen and bituminous mixtures. The model, which is based on dissipative particle dynamics, consists of different dynamical entities that represent the different characteristic time scales. Through the stress relaxation function, the mechanical properties of the model are investigated. For pure bitumen, the viscosity features super-Arrhenius behavior in the low-temperature regime in agreement with experimental data. The frequency-dependent viscoelastic properties show purely viscous behavior at low frequencies with increasing elasticity and hardening at higher frequencies, as expected. The model dynamics are analyzed in the framework of longitudinal hydrodynamics. The thermal process is two orders of magnitude slower than the attenuation of the density-wave propagation; hence the dynamic structure factor is dominated by a sharp Rayleigh peak and a relatively broad Brillouin peak. The model is applied to study triblock-copolymer-modified bitumen mixtures. Effects of the polymer concentration and end-block interactions with the bitumen are investigated. While the polymer concentration has an effect on the mechanical properties, the effect of increasing repulsive interactions between the bitumen and the polymer end-blocks is much more dramatic; it increases the viscosity of the mixture and shifts the onset of the elastic behavior to lower frequencies. For increased repulsion, the polymer end-blocks form small clusters that can be connected by a dynamic polymer backbone network. A simple Flory-Huggins analysis reveals the onset of segregation of the end-blocks in the bitumen mixture in agreement with the simulation data. Hence the changed mechanical properties are due to the emergence of large-scale structures as the repulsion is increased, which conforms to known mechanisms of microphase separation in polymer-modified bitumens.

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“…69,70 Therefore, often simulations with NH or dissipative particle dynamics (DPD) thermostats are employed instead. 40,69,71 For NH, it is known that self-diffusion and shear viscosity are adequately derived. With DPD, also accurate bulk viscosities are accessible, despite the reduced capability of DPD thermostats to control temperature.…”

Section: Homogeneous Systemsmentioning

confidence: 99%