MPC without Hydrodynamics

The importance of hydrodynamic interactions (HI) in complex fluids is generally accepted. A standard procedure for determining the influence of HI is to investigate the same system with and without HI. In order to compare results, however, the two simulations must differ as little as possible - apart from the inclusion of HI. A well-known example of this approach is Stokesian dynamics simulations (SD), where Ihe original BD method can be extended by inclnding hydrodynamic interactions in the mobility matrix by employing the Oseen tensor [6,12]. 

The random MPC solvent therefore has similar properties to the MFC solvent, except that there are no HI. The relevant parameters in both methods are the average number of particles per cell, M, the rotation angle a, and the collision time At which can be chosen to be the same. For small values of the density (Af 5), fluctuation effects have been noticed [26] and could also be included in the random MPC solvent by a Poisson-distributed density. The velocity autocorrelation functions [15] of a random MPC solvent show a simple exponential decay, which implies some differences in the solvent diffusion coefficients. Other transport coefficients such as the viscosity depend on HI only weakly [57] and consequently are expected to be essentially identical in both solvents. 

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