Simulation of high Schmidt number fluids with dissipative particle dynamics: Parameter identification and robust viscosity evaluation

Abstract

Dissipative particle dynamics (DPD) is a widely used coarse-grained technique for the simulation of complex fluids. Although the method is capable of describing the hydrodynamics of any fluid, the common choice of DPD parameters, such as friction coefficient γ, dissipative cutoff radius r D c , coarse-graining factor N m and weighting function exponent s, unrealistically leads to the simulation of liquid water with a low Schmidt number Sc at standard pressure and temperature. In this work we explored the influence of these parameters, finding the set of parameters needed to properly simulate liquid water. Particular attention was devoted to the numerical techniques to calculate the transport properties from equilibrium simulations, especially in the calculation of the viscosity, comparing the most commonly adopted techniques and formulating a recipe that can be used for further investigations.

Transport coefficients from Einstein–Helfand relations using standard and energy-conserving dissipative particle dynamics methods

“…More recently, Panoukidou et al 29 proposed an EH relation for the shear viscosity of a DPD polymer solution derived from the expressions of Ernst and Brito. Although some authors have applied the traditional GK and EH expressions to DPD with success, 30 the apparent community opinion is that GK and EH methods are problematic when applied to DPD systems, and require specifically derived formulas, including complex formal expressions for the observables, which are cumbersome.…”

Green–Kubo expressions for transport coefficients from dissipative particle dynamics simulations revisited

“…To test the validity of the GK expression eqn (32), with the stress tensor given in eqn (30), we calculated the viscosity independently from a series of non-equilibrium DPD simulations. For the latter, the box length in the x-direction, L x , was twice as large as in the other two directions, i.e., L y = L z = L x /2, and periodic boundary conditions were applied in all directions.…”

DPD Modelling of the Self- and Co-Assembly of Polymers and Polyelectrolytes in Aqueous Media: Impact on Polymer Science

“…The results of these studies, supported by a number of specific application-orientated papers, indicate that the DPD simulations of static equilibrium properties of polymer systems (including the studies of the polymer self-assembly) based on the mass of the bead, m, cut-off radius, r C , energy in k B T and the time unit defined as τ = r C [m/(k B T)] 1/2 correctly reproduce the experimental behaviour in the whole mesoscopic range, provided that the relative differences between interactions of individual components have been set appropriately. However, the simulations of dynamic properties, which are not a topic of this review, require the appropriate setting of parameters, particularly the recalculation of the time unit at a given coarse-grained level [102,[137][138][139].…”