Numerical investigations on the compressibility of a DPD fluid

Pan, Dingyi; Phan‐Thien, N.; Mai‐Duy, N.; Khoo, Boo Cheong

doi:10.1016/j.jcp.2013.02.013

Cited by 32 publications

(25 citation statements)

References 30 publications

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“…Polymer melts and solutions, as well as multiphase systems have also been studied with special emphasis on their rheological behavior using DPD [9,16,17]. However, one can conclude from a careful review of the prior publications that, even for the simplest system (water, first studied by Groot and Warren [2]), values reported for the viscosity vary from one report to another, depending on the type of flow and method used for calculation of viscosity, boundary conditions and the choice of force parameters [17][18][19][20]. In particular, different viscosity values from Green-Kubo [21] expression for stress autocorrelation function (zero-shear viscosity), stress tensor for steady shear simulations, Poiseuille flow and transient startup shear flow have been reported.…”

Section: Introductionmentioning

confidence: 99%

Viscosity measurement techniques in Dissipative Particle Dynamics

Boromand

Jamali

Maia

2015

Computer Physics Communications

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a b s t r a c tIn this study two main groups of viscosity measurement techniques are used to measure the viscosity of a simple fluid using Dissipative Particle Dynamics, DPD. In the first method, a microscopic definition of the pressure tensor is used in equilibrium and out of equilibrium to measure the zero-shear viscosity and shear viscosity, respectively. In the second method, a periodic Poiseuille flow and start-up transient shear flow is used and the shear viscosity is obtained from the velocity profiles by a numerical fitting procedure. Using the standard Lees-Edward boundary condition for DPD will result in incorrect velocity profiles at high values of the dissipative parameter. Although this issue was partially addressed in Chatterjee (2007), in this work we present further modifications (Lagrangian approach) to the original LE boundary condition (Eulerian approach) that will fix the deviation from the desired shear rate at high values of the dissipative parameter and decrease the noise to signal ratios in stress measurement while increases the accessible low shear rate window. Also, the thermostat effect of the dissipative and random forces is coupled to the dynamic response of the system and affects the transport properties like the viscosity and diffusion coefficient. We investigated thoroughly the dependency of viscosity measured by both Eulerian and Lagrangian methodologies, as well as numerical fitting procedures and found that all the methods are in quantitative agreement.

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Section: Introductionmentioning

confidence: 99%

Viscosity measurement techniques in Dissipative Particle Dynamics

Boromand

Jamali

Maia

2015

Computer Physics Communications

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“…We employ several sets of colloids: (1,2,3,4,6,8), corresponding to volume fraction in range of 0.0204 to 0.1429. Figure 12 shows good agreement between the present relative viscosities and those predicted by (53) as φ approaches zero.…”

Section: Particulate Suspensionsmentioning

confidence: 99%

“…In [6], the equivalent Poisson ratio of a DPD fluid (a measure of compressibility) in the absence of conservative forces was estimated as 0.24, and measured in a simulated four-rolled mill at a value of 0.48 (at best), less than the incompressible limit of 0.5. This compressibility nature of a DPD fluid implies that unwanted effects due to compressibility of a DPD flow will occur, and special care is needed in interpretation of the flow results, especially at high Re number.…”

Section: Introductionmentioning

confidence: 99%

Strongly overdamped Dissipative Particle Dynamics for fluid-solid systems

Phan‐Thien

Mai‐Duy

Khoo

et al. 2016

Applied Mathematical Modelling

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In this paper, a numerical scheme is used to study strongly-overdamped Dissipative Particles Dynamics (DPD) systems for the modelling of fluid-solid systems. In the scheme, the resultant set of algebraic equations for the velocities are directly solved in an iterative manner. Different test problems, e.g., viscometric flows, particulate suspensions and flows past a periodic square array of cylinders, are used to verify the proposed method.In the simulation of particulate suspensions, a new simple model for massless suspended particles is presented. A DPD fluid in the overdamped limit is shown to possess several attractive properties including much faster dynamic response and near-incompressibility.

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“…Keeping the dissipative and random forces unchanged, an increase in the repulsion strength a ij will promote incompressibility of the DPD fluid [24]. However,…”

Section: Role Of the Conservative Forcementioning

confidence: 99%

Investigation of particles size effects in Dissipative Particle Dynamics (DPD) modelling of colloidal suspensions

Mai‐Duy

Phan‐Thien

Khoo

2015

Computer Physics Communications

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In the Dissipative Particle Dynamics (DPD) simulation of suspension, the fluid (solvent) and colloidal particles are replaced by a set of DPD particles and therefore their relative sizes (as measured by their exclusion zones) can affect the maximal packing fraction of the colloidal particles. In this study, we investigate roles of the conservative, dissipative and random forces in this relative size ratio (colloidal/solvent). We propose a mechanism of adjusting the DPD parameters to properly model the solvent phase (the solvent here is supposed to have the same isothermal compressibility to that of water).

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Numerical investigations on the compressibility of a DPD fluid

Cited by 32 publications

References 30 publications

Viscosity measurement techniques in Dissipative Particle Dynamics

Viscosity measurement techniques in Dissipative Particle Dynamics

Strongly overdamped Dissipative Particle Dynamics for fluid-solid systems

Investigation of particles size effects in Dissipative Particle Dynamics (DPD) modelling of colloidal suspensions

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