Limitation of stochastic rotation dynamics to represent hydrodynamic interaction between colloidal particles

Abstract

Stochastic Rotation Dynamics (SRD) is a valuable numerical tool extensively used in many domains of hydrodynamics simulations including colloidal suspensions. We investigate the dynamics of two colloidal particles in the regime of low Reynolds number by means of SRD in 3D. In contrast to well-known analytical and experimental results, no long-range interaction between the suspended particles could be found, independent of the size of the particles and the Mach and Péclet numbers. We attribute this behavior to the compressible nature and low sound velocity in the SRD solvent. The inability of representing long-range interactions poses an important limitation to the applicability of SRD to certain physical systems. We provide an estimation of typical length scales for which SRD can be applied. Published by AIP Publishing. https://doi.

Chemically specific coarse‐graining of polymers: Methods and prospects

“…Irrespective of the precise implementation, MPC has been used in the simulation of numerous polymeric systems, [72][73][74][75] although mostly in a phenomenological setting. One challenge for chemically specific simulation using MPC is that a physically motivated mapping of solvent chemistry to MPC parameters (namely, cell size, particle density, and collision frequency) can result in significantly reduced solution viscosity and too rapid solvent diffusivity, [76][77][78] but further modification of the parameters would substantially increase the computational expense associated with the method. For an excellent review on the technique, additional considerations, and recent applications, we refer readers to Reference 79.…”

Diffusion and sedimentation in colloidal suspensions using multiparticle collision dynamics with a discrete particle model

“…The divergence of M is taken with respect to R. 9,50 The hydrodynamic interactions that are present in the simulations are determined by the choice of M. Stokesian dynamics includes both near-field (lubrication) and far-field coupling in M and can also include torques and stresslets, 13 but has a corresponding large computational cost. Here, we use the simpler but reasonably accurate approximation that the entries of M are given pairwise, (12) ... M (21) M (22) ... . .…”

“…The fundamental differences between the MD+MPCD and BD+RPY simulations at short times might be understood by considering the time scales at which hydrodynamic interactions propagate. 22 In BD+RPY, the solvent-mediated coupling between the colloids is instantaneous and only depends on their positions, whereas in MD+MPCD, shear and sound waves propagate with finite velocities v h ∼ /ν 0 and v c ∼ k B T /m = /τ , respectively. The resulting time scales τ h ∼ a/v h and τ c ∼ a/v c are comparable to the typical time τ B at which Brownian motion of the colloids sets in.…”

“…It was argued in Ref. 22 that this lack of time scale separation may cause incomplete hydrodynamic coupling at short times.…”

“…Hence, these approaches are generally more compatible with complex particles and geometries; however, there are still active questions about how the solvent properties and coupling scheme affect the hydrodynamic forces, and in particular, whether they reproduce low-Reynolds-number results in appropriate limits. [20][21][22] The focus of this article is on the MPCD method, which is the newest of the three mesoscale approaches listed above. In MPCD, the solvent is modeled as point particles that interact with each other through stochastic collisions in spatially localized cells.…”